Electric Vehicle Forums - Bad Ecu Question

So i had a bad ABS pump and cost me 500+ to fix. I took out some relays and caused a battery drain and caused my ECU to break too.

Found the drain - replaced the 2 relays - and ABS installed now i have a bad ECU

1. I need to find the EXACT part number for the ECU for my car - no idea how since the part shop here does NOT give out part number so i dont go out and buy my own. Screw You Toyota.

2. How do i reprogram the ECU?

Im buying it used and im afraid that i wont get the right ECU or one with bad programming not fitted for my car. or maybe im just over stressing it.