Very slow to shift into drive?

To cut to the chase, yes this vehicle is old but he's a Toyota. He has worked very reliably for about 6 years. Check engine light has been in since I purchased him. I began to smell gas when he started up so I ran some codes and got P0401, P0770, and a code for the O2 bank 1 sensor. My main concern in P0770, he is very slow to shift in to drive. Usually he won't actually slip into drive until he's warmed up. After he is, the transition from first to second gear is really rough and his acceleration is virtually nothing. He can switch to all the other gears just fine. I cannot afford the $400.00 purchase of the transmission shift solenoid e to attempt to fix it. But I had it run in an OBD-2 (obd-ll) reader at AutoZone and they said they only have the one solenoid for $400.00. What can I do? I've done plenty of small time repairs like oil changes, brake pads, air filter, thermostat replacements, but I'm not sure what to do about this. I sadly cannot afford another vehicle.