Watch videos on youtube of how to build a PC. Its really not that hard. Here, take a look at this parts list. To get a PC this good prebuilt would cost you at least another $350
Here, this is the best prebuilt one I could find for anywhere NEAR your budget, and I still would not buy it, its parts are FAR lower in quality than the list I just posted, especially its power supply, which is only a 350W, which eliminates any future upgrades. http://www.newegg.com/Product/Product.aspx?Item=N82E16883229438
You could write down a list of pcs that you have at a shop near you and we could help to choose if you want. Do you mind ordering online? Theres a wider selection, though shipping costs might be pretty painful.