Man, I say just suck it up and do it yourself. $200 for the used ecu, $120 for the knock sensor, and $15 for the toyota fiph sealant. 4 hours later and you have a better car. Here is the post for the install. Post to install
The link is few posts down...I tried to just post the link,but it won't let you write new celica.org all together on this site and it is in the url...weird.
You just need to read through the install a few times and get familiar with it all. It is really detailed and tells you everything. I am doing this install/fix myself today...good times. I am not sure if you have acquired the parts needed yet, but thats what I would get done asap. The ecu isn't always easy to come by used since you need a 2000 or 2001 and the dealership will charge upwards of $800's if you go that route.