Camera problem - quick fix or get another?

Esqui

Ayup, MSE.

A few weeks back, I got a Panasonic FS12 camera as a replacement for my sadly-departed FX12. It's been pretty good, but after trying to take some pictures of the Bournemouth Air Show today, I'm not so sure.

It takes far too long to focus on anything more than a few metres away, and loses that focus quite rapidly. I don't know if I'm just using it in the wrong mode (there's not really a lot that's good for taking pictures of fast-moving things in the sky), or if it's the camera. I know it's not as high-spec as the FX12 was...and I'm not expecting expert-quality photos, but I'd like something that isn't blurry. I did get a small amount of sand in it recently, and I'm guessing that might cause it to not focus properly.

So, with that all in mind, my question to you people is... Is there anything I might be doing wrong, or should I swap it for another? (In which case, a recommendation for something about £100 from here http://www.currys.co.uk/gbuk/digital-cameras/344_3199_30301_xx_xx/xx-criteria.html?sPageInfo=1_10 would be wonderful - I'm not after anything to take expert photos, but enough to get decent snaps of whatever I point it at. I know I'll not be getting a whole lot for that money.)

As you might expect, I know enough about cameras to work them pretty well - and see what looks good on paper. But I don't really get a chance to find out the practicalities of owning them, and was hoping someone here may have some experiences with the other ones.