I thought i posted how to add tabs somewhere but I can't find it. Ill work on that in a little while.

For getting your Add to Cart tab first, you can A) leave Product description & any custom tabs off, which leaves the Add to cart to be first. Or if you still want Custom/Prod Desc tabs, then you can use a version of TPP I made that puts the custom/prod desc tabs at the end instead of the beginning.