If you have to ask, it's too involved, no sarcasm meant. Don't even consider it unless you have the factory service manual at hand. Replacing a head gasket on older Chrysler products is about as easy as they get, but there are a pile of things professionals do to prevent repeat problems. Surface prep is critical so the new gasket will seal properly. The head must be checked for flatness within.002 inches.
Fords are more difficult to work on than Chryslers, and the Ford Contour / Mercury "Mistake", (mechanic's terminology), have a whole pile of additional issues. Even professionals get real frustrated over shredding timing belts. The problem is the design, not the mechanic's skill and experience. These are well-known problems that make mechanics cringe when these cars come in for service. This is one model you don't want to learn on unless you don't mind doing the job over three or four times.
You can expect to pay around $500.00 to maybe $700.00 for the head gasket service. Your mechanic will want to replace the timing belt right away since he's already in there. That will save you the cost of that maintenance repair in the future.
You might be able to handle the power steering pump yourself. Fords have a lot of trouble bleeding the air out of the system. It's common for the system to work fine while the engine is running, then blibbet out a bunch of fluid onto the ground when you stop the engine. That will continue until the air works its way out. It may also make a loud buzzing noise until that air is gone. It often takes weeks for the air to totally leave the system.
You might consider visiting one of the salvage yards where you pay your buck and take your tools in for the day. Pull the pump off a similar car, then decide if you want to tackle that repair on your car.