There's no set time, everyone's body is different. I'm trying to get down there too and I've been stuck at about 141-142 for.... gosh, I don't know how long now.
If you're eating right, watching your calories and doing all the right things, it will come off eventually. The last few pounds are the hardest because your body resists letting go of the weight. Just make sure you're not eating more calories than your body needs. If not, just give it time, it will come off