stalling

I have been on MFP for about 6 months now and have lost 27 pounds. But lately I am stuck!!!! I am suppose to eat around 1600 calories a day but try to stay around 1300 and I walk 4-5 days a week and when I weigh I will either be up 2 pounds or back down to my steady weight of 177. My goal is still to lose 18 to 22 more pounds so I need to find some way to get my self kickstarter before I start being depressed and risk quiting. Help!