meh...uhhh WAITZ FOR CRISTMAZ!
Ask for a GT640
or an HD7750 for Christmas. Your choice between ATI or Nvidia.
GT640 =
http://www.newegg.com/Product/Product.aspx?Item=N82E16814127686HD7750 =
http://www.newegg.com/Product/Product.aspx?Item=N82E16814102969Both are close to $100, give or take a few dollars. And you're not just limited to the 2 links above. Both are
nearly equivalent to each other in terms of how they run games. Both do not need power connectors to install them; you just slide it into the correct slot after removing the silver backplate. If you don't understand that, ask your dad or someone better to install it.
Personally, I recommend the GT640. However,
if you can find one of these inside your computer,
...then go for the GTX650 or HD 7770. $20 more, but nearly 50% better. If you were to go any higher than that, you'd jump the $200 barrier easily. Trust me, its worth it.
On the other hand, if you cant find one of those, dont worry about it.
You just wanna play Blockland with shaders don't you? A GT640 or 7750 is
probably more than enough.