I use Sound Forge 4 and it is an excellent app.
it does have some wonderfull features. You can resample to speed or slow a section which would restore stretch but you would have to determine where the variations were and presumeably they occur in sections and vary. It would be a slow process but if it's worth it. You can even slow/speed without changing pitch but it can introduce echo if pushed too far.
I couldn't find the feature in a hurry but I was sure it did an FFT (Fourier) which could help you measure the stretch as long as the original was in tune!
recording is easy use the earpiece o/p into mic input on the sound card. How high a fi do you want? - Oh yes record in 16 bit. 8 Bit can sound good enough until you burn a CD and listen on earphones. 16 is adequate for all but the youngest ears and pedantic ones at that.