No, it won't work, all AM3+ CPU require an AM3+ motherboard. I think there were some AM3 CPUs that could work on some AM2+ boards, but that's it. Your board does actually support some AM3 processors eg. Athlon II and Phenom II, but they are all very low powered models with a 65 Watt TDP or lower, and have pretty low clockspeeds as a result. The Phenom II X4 910e would be the best of those your board supports, but it's only clocked at 2.6GHz and you may have a hard time finding one now, it wasn't a very commonly used CPU.
You're probably best off saving up some more money and getting a new motherboard and RAM alongside a new CPU, there just isn't much you can really do with a motherboard that outdated.