Two options I can offer...
1. Move the computer mount to your seat post if the diameter of seat post allows. I did this a few years ago and the cable was long enough so that I could mount the pick up by the back wheel. See pic below..
2. See if they make an extra long wire mount for your computer. I bought one for mine a couple of years ago (I got tired of looking between my legs to see how fast I was going on the trainer), it was like $12 from Performance.
Hope that helps!!!