At your weight, stay with a hardtail. You won't gain anything from full suspension and will lose pedaling energy as it oscillates. Plus, I don't know of ANY rear shock that will hold your weight and be reliable over the long haul. NONE.
I am also asking the question of what a new bike will do for you that the old one won't. N+1 is a resistible affliction but we have to have all the facts to help you find the one true path.