I'm not really sure what your question is. Your cpu came without a heatsink and you need to buy one? Or you want to upgrade your stock heatsink??
If the cpu cooler you buy says AM3 compatible, its AM3 compatible, whether or not you think the bracket looks like it will work.
My question is more: How does that v shaped bracket work or fit onto the mobo/ is that the only option of am3 boards?