How do I not gain weight when I get this job on Monday as a merchandiser? I'll be standing on my feet for 8

hours, 5 days a week and I want to no what I can do to lose weight (30 pounds) and keep the weight off while on my feet. I'm married with 2 kids and a husband. I go to school 2 nights a week for 4 hours. I work out 55 mins each day 5 days a week and 3 days after the work out I go to the park with my kids to exercise for an hour. I prepare all the meals for my family and I do all of the cooking and cleaning. Please tell me what to do; what to wear and how to eat as I wan to lose the last 30 pounds by y October 2009. And I don't want to gain weight as I'm afraid standing for so long may cause the weight gain.