You need to raise more on the flop.
agreed, with the pot at ~ 12 coming to you, raising to 7 gives your opponents ~5 to 1. way to cheap of price when you almost assuredly have the best hand. i like a raise to 12-15. on the turn and river, you need to raise all in. players at this limit will call with crap so often, you are missing a lot of value by not getting your stack in here with TPTK.