How should I upgrade my computer

I'm looking to upgrade my pc I have this: http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=3499704, I would like the put a Radeon HD 7770 in or something comparable to that. What upgrades would i have to make?

If I were you, I'd buy an 80+ Silver/Gold certified power supply with a little more wattage, and then you should be able to just open up your tower, and switch out the cards (so long as the gpu that you're buying is the same size, or fits your case)

would this http://www.newegg.com/Product/Product.aspx?Item=N82E16817104180 and http://www.newegg.com/Product/Product.aspx?Item=N82E16814202011 work well together?

hmmmmmmmmmmm....should do, but if you're willing to wait (im so sorry about the super delayed answer, ive just been swamped with school and unable to come online in a while), you can always just save your money until Black Friday where the GTX 770 and 780, Radeon 7870 and 7970 are gonna go on sale really cheap (in comparison to their normal price). Also, make sure that your motherboard will support GDDR5, and make sure it can handle the watts/volts. Again, sorry for the SUPER delayed answer. I've just been swamped at school and i haven't even come online except today to check my stuff. So....yeah. and if I were you, I'd also upgrade the RAM, because it's better to have matched RAM as oppose to unmatched, because matched is beating unmatched in the benchmarks as Logan said in his video on the Kill Your Mac Pro video:

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&ved=0CCkQtwIwAA&url=http%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DKeIW7PAi6_o&ei=ztCSUtf7Msf9oASf9YKgAw&usg=AFQjCNHbQGAOle2QWriXUsqMcJAWjNGT0Q&bvm=bv.56988011,d.cGU

 

So you should upgrade to 16gb ddr3 running at 1600mhz

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&ved=0CCkQtwIwAA&url=http%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DKeIW7PAi6_o&ei=ztCSUtf7Msf9oASf9YKgAw&usg=AFQjCNHbQGAOle2QWriXUsqMcJAWjNGT0Q&bvm=bv.56988011,d.cGU

 

As for your power supply, it's always good to go a little overboard, because it (along with your motherboard) future proofs your build. a Gold+ power supply is great, but Silver+ works too. And  a modular/semi-modular PSU also keeps wires out of the way, routing is easier, and it helps air flow, because you can actually route the damn things.

 

again, sorry for the big delay in response.