Mine is doing the exact same thing - makes same noise (even down to the squeaking noise turning into more of a putt putt putt). I just got the gasket set and head bolts in the mail today. I'm going to attempt to do it myself. If you haven't seen this video yet, this guy does a really nice job going thru the procedure:

 

This gasket was really starting to deteriorate. You can easily see that there was no gasket material left between the cylinder and the outside air:



This picture shows the path the burnt gasses were taking out the exhaust manifold side of the heads:



It started out as a high pitched squeak and then eventually turned into a putt putt putt sound.

Head gasket job took me about 15 hours. I did a ton of research on it and studied the RAVE manual a bunch too, but mine went pretty much just like the one in the video I posted in the previous post.

 

Sorry for such a late reply but thanks for this and hope you're fix is going / went well. Cheers!