I know it's frustrating to say that you have never even changed your oil, and then everybody keeps saying do it yourself. But, you are a member of a forums where at least 50% of us entered here the same way or close. With the help of these forums, you can do anything you want. If you are not interested in doing any maintanence, it's gonna be a very expensive car to drive.
As for your current situation.................I'd definitely get a second opinion on price for that work. It's probably not a job that you are ready for just yet. A stock clutch kit new can be had for under $250, and the clutch master about $50. Not long ago, I paid $175 to have a tranny and clutch swapped out. So, $500 would be more reasonable if you paid somebody to do it.
Then once it's running again, you should decide what to do with the car. If you keep it, you can't just drive the piss out of it, and expect to keep driving it for long periods of time without working on it. Either sell it, and only lose a little of the money you have invested. That amount will be dwarfed by what you could end up dumping into it, if paying to have it fixed constantly. Or, decide to learn a little of what is here at Supramania, and do some of your own work. Start small, and gain confidence with each success. It's not as hard as it looks. People are more than willing to help if you are putting forth a little effort.
EDIT*********** Damn I hate when I post and then see that page 1 was not the only page! Going to read the rest now.