Hi Susan. Look for a 26W CFL, or a bright LED bulb (LED is expensive)

The heat from a "replacement" type CFL with an integral ballast can become overheated in an enclosed fixture that was designed for a low wattage incandescent lamp.

When the fixture overheats it should shut down and come back on when it cools so if it does that stop using the larger lamp.

Shower lights that produce a lot of light are low voltage with 50watt MR16 lamps.

To better answer your question you need to tell us what the fixture brand and model # is. It appears to be the type with its own reflector that uses a 40 to 60 watt A19 lamp (standard incandescent light bulb). What you want to use is a halogen PAR lamp that has its own reflector built into the lamp. If the manufacturer doesn't list that type of lamp for the fixture, you need to replace the fixture.

Right on about the Par bulb. This is another case of an Electrician installing products without determining the needs of the customer...makes me crazy! Depending on the housing he installed, you may be able to purchase a shower trim that is made to use with a halogen par bulb. A 75 or even 50 watt halogen should solve your problem. Juno Lighting makes one for sure. Find the brand of your housing and look for a wet rated par trim to solve this problem. One solution that will not meet code is to use a Par bulb that fits in the trim you now have, remove the glass and a Par 38 size should fill the trim hole nicely if you have a 6" housing. The Par 38 is a wet rated bulb and make sure you buy one that is double cased, 2 layers of glass. This is the same bulb that is used outside in flood lights. The double casing will protect you should the interior glass break (which rarely happens anyway.) The proper solution is to find the trim I mentioned above that is rated to be used with your housing. All recessed housings are damp rated anyway so you will not hurt the housing. They are often used outside in overhangs with open trims. Just be sure that you use the waterproof Par 38 if you go with the open solution. If your housing is not Juno, the Juno trim may still fit. Just remember that when you mix a housing and trim from different manufacturers, you void the UL listing on them both. This is not dangerous as long as you stay in the wattage recommendation. Start by checking if your housing brand has the trim I described. A shower or wet location trim that takes a 50-75 Watt Halogen par bulb. This may be either a Par30 or Par38.