Chances are that you don't need a better camera, just the ability to take better pics with what you have got. I have a 7 year old Canon Powershot A40 2MP which (admitedly with my limited photographic knowledge) takes pics just as good as my Canon 400D SLR. OK so the A40 is a smaller file size that you can't print out large but for posting on here 2MP is fine....or 3 MP in your case.
Make sure you use a tripod and the timer function so that there is no chance of camera shake. I also set the mini up and then use all of the optical zoom ( NOT the digital ) and place the camera back from the mini so that you get a nicely framed shot. By having the camera as far back as possible you increase the range of distance in which the mini is in focus.
I would say don't buy a new camera, learnt to use what you have got. If you want to spend the money see if you can find someone you can pay (ie a professional) to show you how to take pics of minis. That will be far more useful in the long term.