Since that Motherboard is Socket 939 (or so Google says) there is no upgrade path, least not one worth it.
If you want to stick with AMD, look for Socket AM2+/AM3, Intel look for LGA 775 or 1366 I think it is.
As Fulmar said, those parts replaced would be the only way.
As for suggestions, I personally stick with AMD (Price), and I use Biostar Motherboards and am going for an AMD Phenom II X3 720BE soon and use 2GB of DDR2-800MHz RAM. Price is about 200-210$ for that.
A word of warning though, if you go with AMD, do not buy one that says "AM2+/AM3 (with BIOS update)", that means you'll need a Socket AM2/AM2+ installed then upgrade to AM3.