Suggestions needed...

I've got some footage (just a few minutes) of vehicles which have military markings painted on them but due to problems with extras on shooting day we had to use vehicles with the wrong country's markings sooooo armed with a copy of After Effects I've got the job of removing or replacing 15 american white stars... I first tried manually rubber stamp tool'ing in photoshop but as you can imagine this looked terrible. I've also tried with a single tracking point and attaching a cleaned image of the affected areas but perspective and shadows meant that this didn't work either... Does anyone have any suggestions or can anyone point me in the direction of some specific tutorials or books that may help me out?

Thanks in advance!