Ugh. You really screwed yourself mate. It doesn't have a lot of options in the way of upgrades. According to the specs its DDR1 RAM which isn't worth buying, doesn't specify if it has a PCI-E x16 slot, and the PSU is probably too weak to support any GPU worth buying anyway. You really should've checked with us before buying.
Edit: Your edit confirms it. There is literally nothing worth the price of upgrading in this machine.
www.newegg.com
You'd ALWAYS be better off building your own. It brings the price down immensely.
The build in the thread DTBK linked to would be cool.
Quote from name:BluEditor
How exactly on Newegg did you know I didn't have much options for an upgrade? Do I just type in the name and see what newegg recommends?
Okay, I will build a computer, but how much money would I save? I really just want a computer that can atleast play SC, and do some other programs that might be a bit more intense. Not really looking for a gaming computer, more like something I could use at home for a job or school.
He probably knew from the specs website you gave. Since it does not have pci-e you cant seriously upgrade gpu and I am not even sure its atx form factor. You can get more ram but its ridiculously expensive because its ddr. That ebay computer will play sc but probably nothing more intense

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I am a Mathematician Computer Scientist Logic user

We can't explain the universe, just describe it; and we don't know whether our theories are true, we just know they're not wrong. >Harald Lesch
Yeah, to be fair, that computer will play Starcraft just fine.
ANY computer with at least 1000MHz (for some trigger intense maps) will...
Minimum requirement is 90MHz (granted, you can forget multiplayer with that)