Can someone fix my shower?

If there's water coming from inside the actual case then there is a strong chance of electrocution!!!
With the combined costs of taking 2 days off work waiting for the plumber, replacement parts, labour, and callout charges, you'll probably be better off replacing the whole thing.
If you insist on repair, first make safe by switching off power from the mains.
Next, pull off the temerature dial with a gentle tug, then remove the casing. The screw holding the casing is usually located beneath the small Aqualisa logo, slide a small screwdriver under it and it should fall right off.
Once you've undone the holding screw and removed the casing, check the hot/cold pipes leading into the pump. These are usually push-fit connections.
After ensuring all connections are watertight, replace the casing and dial. switch on the mains power, and give it a try.
Good luck.

Big Softy
June 2006