anti pollution and ESP/ASR fault peugeot 307 GLX HDi 2.0 `02 ?

I have recently purchased a peugeot 307 GLX HDi 2.0 `02 plate but it was a bit lumpy ie.timing out when idling, took to my local garage who changed one of the injectors all ok. Took it for a long drive and it has now got the following faults ESP/ASR fault also anti-pollution not working and it has gone into limp mode it is back to being lumpy when idling, It smells hot when used for very short journeys but seems to be from front exhaust back of engine.
I`m female so apologise for for the wrong terminology.