I'm thinking that should be about a $1500 - $1800 car. It sounds like it runs fine, I'm suprised that it handles good with a broken rear shock. The oil pressure may be a worry though, it should go right to the top with any rpm much over idle - 45 psi on my 79 TD -and drop down at idle.

I'd keep looking, there are probably more out there, that have been better cared for. That car sounds like it has been neglected a bit, but of course any car this age is bound to need some work.