New Laptop Sugggestion

  I am planning on buying a new laptop mainly for my college purposes. I am into gaming   and animation which i do profusely on my desktop but i would prefer doing slight changes on the laptop too (nothing highly intensive) while i am on the move. I expect a battery life of at least 1.5 hours. I have chosen two laptops that is the Acer 5740g. my budget is around 800-900$.
I thought if i could get an alienware but i have no idea on how to avail discounts and coupons   .
There seems to be a guy on you tube who got it for 900$   .
So kindly help me out here and if you have better suggestions let me know   .

Prefrences:
core i5 [sandybridge] or core i7[sandybridge]
atleast 4gb of ram
500gb hdd
any screen size but minimum resolution to be 1366x768
nvidia gt540m and above graphics.

thanks in advance!