Your NVDIA GeForce GT220 1 GB video card supports OpenGL 3.1 so you are fine there. It's not certified for Premiere Pro's Mecury Playback Engine CUDA accelleration, but the Mercury Playback Engine will work perfectly well in software mode. Since your card has 1GB, you can use the well known hack for enabling that card on your system, but it's really under powered for gpu acceleration. It only has 48 CUDA cores. Compare that to the 240 CUDA cores on the supported GT285. I can't estimate how much gpu acceleration you would get. I haven't looked to see if anyone has reported problems using gpu acceleration with the GT220.
That's a slow hard drive. You generally see slow drives like that in portable systems to conserve power and extend battery life. If you have room in the computer case for a second internal hard drive, I would definitely consider adding one and use that for your video projects and media files.
Raid 0 is a way of making two separate hard drives appear as one. The raid controller will write/read both drives simultaneously enabling the reading and writing speed to be faster than a single equivalent drive. However, because data is divided between the two drives, if one drive fails, you lose everything on both drives. You only need raid 0 if you are reading or writing huge amounts of data and the speed of the drive is a bottle neck. For video, that typically happens when you are working with large uncompressed video files. Unless you deliberately create uncompressed files yourself, you won't be working with them. I wouldn't worry about raid 0.
Your cpu is fast, but it only has two cores. That could be a problem if you are working with highly compressed video such as AVCHD. Generally, it's recommended that you have a cpu with four cores if you will be working with AVCHD. Your cpu does have hyperthreading which will support four threads and look like it has 4 cores. But, for highly cpu intensive tasks like video rendering/encoding, you will only see a minor improvement. You really do need 4 real cores for AVCHD and not virtual ones.
I agree with Chuck. If you are satisfied with the performance of Premiere Elements now, you should have a similar experience with Premiere Pro for comparable projects.