Tthreaded forks cannot be converted to threadless. Even if there is enough extra length to accept the stem clamp, the threaded section is too weak to take the forces. To go threadless you need a new fork, headset and stem.
A work-around is to use a quill adapter in your current threaded fork. These are a straight quill that goes into the steerer like a quill stem but then accepts a threadless stem. These allow you to use either a 1" or 1-1/8" stem and the newer 31.8 mm diameter handlebars.
Here is one: http://www.nashbar.com/bikes/Product_10053_10052_175545_-1___202442
Converting a 7-speed to an 8/9/10-speed requires a new freehub body (8/9/10-speed is wider), removing some spacers from the non-drive side, recentering the axle and redishing the rim to center it properly. I believe your 970 has either 130 mm or 135 mm dropout spacing and your current hub matches it so you won't have to spread the stays. Of course along with the new freehub body, you will need matching shifters, cassette and chain so this can be a relatively expensive conversion.