Your system will support a SSD just fine.
1. Ignore the points which others bring up here and on other threads regarding SATA II vs. SATA III - the extremely high majority of people do not have machines or applications that will make use of sustained throughput capabilities over 3 Gbps which SATA II (theoretically) maxes out at. Generally, the only time you'll see the higher SATA III speeds achieved will be when using a benchmark test - and to go out of your way to see a big number for the sake of a test is silly. Real world day to day usage will not require those higher speeds for any sustained period. Over short bursts, you are not going to notice. It makes little sense in my view to go out and additionally purchase a SATA III add-in card just to be able to hook a SATA III SSD to it and claim you can achieve SATA III speeds. Just by using an add-in card, you will suffer some performance degradation vs. if the SATA III port were on the motherboard. But again, there is no necessity or wonderous speed/performance increase to be seen by the very high majority of people using SSD on SATA III vs. SATA II - it's mostly theoretical vs. reality. You'll see lots of people going out of their way and proclaiming the big differences, but there isn't.
2. You can use a drive image/clone of your HD onto SSD and it will work just fine with no changes whatsoever - assuming that you first get the data on the original HD to fit into a single partition no bigger than the SSD. If the amount of your HD used is less than the size of your SSD, it is a straightforward process to defrag, then use GParted to resize the partition, and then use Clonezilla to create the image of your HD onto a SSD. Doing that, the cloned SSD will work just fine.
If you are not already running AHCI, then you will have a little more work involved if you want to switch to AHCI - and it is pretty much required that you use AHCI mode to get the best performance from your SSD regardless of the system. But again, whether you actually notice the difference in performance of AHCI vs. non-AHCI is debatable and dependent upon your normal usage. If you are running with Win 7, switching to AHCI can be as simple as just updating the registry entry to start up using msahci, and then switching the BIOS entry to use AHCI. For other MS operating systems it is not as straightforward and not guaranteed to support AHCI (Win 2000 with Intel chipset for example). I am not familiar with AMD CPU/chipset so have no words of wisdom for your configuration.
6 SSDs worth of experience (4 different models from 3 different vendors, all running fine, never any glitches) here with machines running Win 2000, Win XP, and Win 7.
Bottom line - purchase the proper size SSD to hold your operating system and installed apps for the least amount of money you can find it. You will be happiest with the speed increase at a reasonable price. Depending on the operating system you're running, something in the 60GB to 96GB range should be sufficent. I'd say for most people under normal circumstances, there's no real need for any more than 128GB. On my Win 2000 Server, I'm running with dual 64GB SATA III Crucial SSDs, and to be honest, even with the machine built for speed, it would probably be just as good with dual 32GB SATA II.
Don't go overboard if you don't have the need.