Yea, you are gonna have to buy a new case, mobo, fans, memory, to start out with.
A new ATX mobo will not (in most cases) fit in that compact case.
Since Compact is a propriatory system only compact components will work in the case and mobo.

Get a good case, the Chieftec (alienware type) cases are about $100.00 and they include a good 420 Watt PS.
The memory DDR2700-DDR3000 will cost about $140.00-$160.00 depends on the brand.
The A7N8X/dx mobo will cost you about $145.00, and the case fans (good ones) are about $5.00 each. (you will need 5, 80mm fans).
This is a total of about $420.00, but this is an excellent platform to build on for a long time, and a super platform to install the Radeon 9700 Pro.