Upgrading Acer Aspire 7540...

Hey Gamespot, just got a new laptop for school, the acer aspire 7540. I want it to be able to actually play some games, so I'm trying to upgrade from my crappy ati mobility radeon hd 4200. I know this laptop isn't necessarily designed for gaming, so I'm not going for a really high-end card. I was thinking something mid-range like theati radeon hd5770, since I'm kind of on a budget. I'm just wondering whether or not my laptop will actually restrict the graphics card's capabilities.Any recommendations as to how to increase my laptop's performance are appreciated.

As a secondary question, will my laptop run games like Mass Effect if upgraded?

Here are my specs as of now:

Processor: AMD Turion II Dual-core mobile M500

Memory: 4096 MB RAM

Graphics Card: Ati Mobility Radeon HD 4200 (dedicated)

oh... (sound of all hope being destroyed) well, thanks, i guess. knowing a little more about computers could have just saved me about 20 minutes...

thank you very much, but for the record i did not buy this laptop primarilyfor gaming, i was hoping it would serve as a multipurpose machine.