Clean the engine bay really well and find exactly where the oil leaks are coming from. You never know, it could just be one nasty oil leak that is spewing gunk all over the engine bay.
Do you have evidence that the head gasket is really bad, aside from the mechanic saying it is? Look under the oil filler cap and see if you see a milky white substance - that would indicate water or coolant in the oil. Are you losing coolant? If you replace the head gasket, make sure you find the reason why it went bad. Make sure the head is flat and not warped, and use new Torx-style head bolts torqued down with the correct pattern (see a service manual). When you do the headgasket, make sure to do the timing belt & water pump at the same time, since they are right there. Oh yeah, don't set the head down on its valves. They will bend.
I doubt it is as bad as you think. It could be something really simple like a leaking valve cover gasket, which makes it look like the rest of it is leaking too. The oil pan gasket is a pain to change out with the engine in the car, but it can be done without a bunch of tools. The head gasket would take a while and is more difficult.. Take it one at a time. If you do it yourself it won't break your wallet too much.
HTH.
-Ben