The supergo is too small for the current rider, hence the long seatpost and riser bars. If you are 'pretty tall' then it will be too small for you as well.
If your bike had quality components I have a hard time giving away late 80s/early 90s MTB frames. Finding a frame on craigslist and swapping might be your best bet. Of course, for $100 for a complete bike seems like a pretty good deal when you consider the hassle.