How do I set a goal wieght?

Hello, i'm not new to MFP but have slacked off after reaching my goal weight in oct 2010. I'm now 12 lbs over that and would like to lose the extra. MFP says if i eat 1200 calories daily I should lose .9 lbs a week. So i'm wondering if I can enter my goal somewhere so MFP can calculate how many weeks it should take? Thanks for your help!