Where can i buy a decent camera lens?

I have a nikon panasonic dmc-g10 and i can find an atachable 52mm lens anywhere and i darent spend all the money on an online site incase its not real or something.
its just the lense i got with it doesn't zoom in much and the manual focus isn't all that good.

The firm in the link will have a fair choice.

As Bazza has mentioned, Jessops is probably the best place to try. I know that when I'm looking to buy a new lens, they are always willing to let me play with the lenses in the store if I take my camera body along. They can help to suit your budget and can guide you to the right lens for the sort of images you're looking to take.

Failing that, PC World do lenses too as well as Currys and I'm sure either of them would be more than happy to help.