Dead transmission on our Subaru (1999; 130k mi). $2300 to fix. Thoughts?

On Thursday, en route to have dinner with Jane, the Subaru's transmission died. I had to get towed off of 101. A local repair shop quotes $2300 to rebuild the transmission. This is the same place that did a tune-up on the car a month ago. They claim this transmission failure is internal and due to a broken pawl, gear, or other. This is independent of the work they did and may have happened regardless. (Another place quoted $3500 for a rebuild.)

So, what now? Fix the transmission? Sell the car as-is and get something else? (Learn how to rebuild transmissions?)

The car is a 1999 Subaru Legacy Outback with 130k miles. We, unfortunately, need it for getting to bike races.