You can't just drop an ECU in I'm afraid. The minimum you will need is an ECU and matched EWS. You will also need to get new chips coded in your keys. Some ebay sellers list with locks and keys too but that shouldn't be necessary. You just need a willing locksmith.
Personally I would send the ECU away to be repaired. Or buy a new ECU and send it away for the old ECU to be cloned onto it. Then you have a plug and play repair. Expect to pay about £200-£250 for that service. But it will save a lot of hassle from doing it any other way.