To be honest, depending on how high you want to go in graphics it might be cheaper to buy another laptop. The item I am talking about is a ViDock ( http://www.villageinstruments.com/tiki-index.php?page=ViDock ).
For the money they want, IMO it'd be cheaper to buy a regular PC -- I've seen kits recently at Tiger/CompUSA/Circuit City in the $300 - $400 range that would do more for less $ [including a graphics card], & I'd be very pessimistic about sticking a decent graphics card inside the housing Village Instruments uses.
Purely FWIW...
Electronics have advanced an awful lot, awfully fast, & if there's a benefit to the current, poor world economy, they've gotten quite a bit cheaper. Purely my opinion, I think many folks might be better off buying a cheap tablet with WiFi or a device made mainly for gaming [e.g. Xbox], playing whatever games they can play with it, vs. trying to update their laptop or netbook or all-in-one or even their PC. For stuff where you don't need or can't have portability, IMO it makes more sense to use a desktop PC, whether instead of or complementing a laptop.
For playing games, including the so-called casual type offered on Game GOTD, the graphics processor is more important than processing horsepower. With most other tasks it's the reverse. While the average on-board graphics chips/circuitry are getting better, their main benefit is low cost & overall small size of the product, whether it's a mini-PC, ultra book or whatever, with most of the effort going into designing something that will do biz &/or school stuff. The same things can often be said for playing video, with many handhelds &/or small devices doing better with HD video [to a HDTV] than many desktop PCs.
That said, the biggest disadvantages of discrete PC graphics cards are size, power consumption, & maybe above all, heat. Good graphics cards are huge, taking up the same amount of room as 2 regular cards because of the heatsinks & fans. If you can physically fit one, you also have to make sure there's enough airflow reaching the card so its own cooling can do the job & not over heat the card, or everything else inside the PC's case. You may have to add fans or in some cases even replace the case. Supplying the needed power is another issue. The power supply's output may have to be double [or more] than what's needed otherwise. Buying a *good* power supply can be difficult -- using sub-standard parts has become such an art form that some factories do stuff like sticking small, very cheap capacitors inside a larger, counterfeit, brand name capacitor housing. As the power supply is the only place in a PC where you have line voltage & current that's not a good thing -- at the least look for a UL listing or the EU equivalent, which a great many do not have. Replacing a power supply isn't technically challenging -- 4 screws & a bunch of standardized cables/ends -- but working in tight spaces with cables that are usually far too long [to fit all sizes of cases] is not a pleasant experience.
If none of that scares you, &/or your PC already meets the requirements, read reviews of any GPU/chipset before you buy -- most ATI & Nvidia card models are pretty equivalent regardless the manufacturer brand. What's important is that both ATI & Nvidia start with their top priced products, then disable features to create lower priced versions, but they sort of guess at how much stuff to turn off -- this means the 2nd or 3rd highest priced card, or even the cheapest may not be anywhere near the best value. Next, decide if you can get away with older technology -- if for example you don't need DX11, you can probably buy an older design card for MUCH less cash... the ATI 6870 was originally over $300 I think, then it started selling for ~$200, nowadays it's ~$140 on sale [often with MIR], but I've seen the really almost as good, 2 generations older 4870 for around $50. And while they may not be absolute top models, those aren't feature limited cards, so the 4870 can outperform limited but current models costing maybe 3 times more.
Otherwise if you're thinking of buying new, generally you can get something that handles general purpose apps, is gaming capable, &/or small, but not all 3. Sometimes buying the right tools for the job you want to do is not only more practical but less expensive too -- I'd rather take the money it'd cost for a relatively large & heavy gaming laptop & use $300 or so for a PC kit from Tiger, ~$100 or so for a small HDTV for use as a TV & a PC monitor, & $300 - $500 on a cheap, small laptop, or less on a tablet if I could use that.
