2hours to get from terminal 1 to 3 at heathrow!Child in tow..is that long enough?

We arrive at terminal 1 and depart 2hrs later from terminal3,my partner is traveling with us as far as london and was wondering if they will be able to help me all the way to terminal 3?I'm unsure if i can check right through from Dublin to our destination so would i have to re-check in at heathrow and if so Im not being convinced that 2hours will be enough time??-although my travel agent said it would be grand!?Please help!!