Can my light fixture be saved?/Visi-therm heater "problem"

I can't find information online about 'living world' tanks/kits, but if it's a light fixture like most fluorescents you can probably replace the switch - you can get all the parts for fluorescent lights at stores like Home Depot. If it's a part that is unique to their products, you may be able to contact the company and order a replacement part, or have it repaired by them (for a fee, I imagine - usually damage like this isn't covered by a manufacturer's warranty).
Not sure about the heater suction cups... all of mine have had a keyhole shaped cutout in the holder, and you insert the suction cups in the larger part of the hole, then slide them up into the smaller part to secure them.

I have no clue what you can do with the lighting but I can help with the heater. The suction cups are really hard to put on. I tilted them as I pushed it in. When I first got mine I went back to the store because I thought it was broken but they were able to put them on.

Wet the suction cup tabs, press them into the holes and twist. They usually pop right in if they're wet. Then slide the heater into the holder and stick it in the tank.

Can't help with the light beyond saying that you can go to Home depot or Lowes and buy almost any switch for Ac lights and install it in place of the broken one.
dave