Time to say byebye to my Yarii - transmission problem

[MyzticZ3r0]

Yesterday, on the way home, a friend and I noticed that my car would rev higher than normal. The check engine light came on shortly afterwards I didn't think too much of it until this morning when I was running errands. The car goes from to 1st to 2nd gear, but no third :(. I took it to my mechanic to find out the codes. I don't have the specific codes on me right now, but it has to do with the shift solenoid in my transmission. I called around to get estimates for replacement. It ranges from 1k to 1.4k to fix with labor, depending on the quality of the transmission. I was intending on selling the car at the end of the year anyways, but I think my plans shifted much sooner than I hoped.

If you are wondering, the car is 2007 and has a little over 107k miles on it. I hear that's relatively low mileage for a transmission to go :(

Edit: The codes that were showing were - P0997 and P0756. The first was the shift solenoid B control circuit "high" and the second was the shift solenoid B CKT performance or stock off. This is the info my mechanic gave me - I honestly do not know what these codes are in reference besides they have to do with the solenoid.