Its that time of year again (holidays) which means weight gain

So I have been struggling a lot lately. I just cant seem to get off the last 15 to 20 pounds in my stomach and thighs. I absolutely hate it beyond words. I have tried diets (cabbage soup diet, calorie intake diet, etc), exercise (low impact with my awful spine), pills , herbs and just cant get it off. OK ya I could stick with the exercise more I know I was doing it like everyday for 45 minutes a day for about a month and I don't really eat more than 1500 calories a day if I am lucky. I mean I might splurge from time to time for a candy or cookie or whatever but it isn't a daily bases. I have alot of medical issues that also doesn't help as well. But this time a year is hard for me because I like to dress up and look nice for the holidays and with my gut I don't. Now I am not severely over weight and most people look at me and say whatever you don't need to lose weight but I do. I am almost 130 and only 5ft 2in. All my life I was around 110. After my first child I was instantly back to 110 then my second I got back to 115 then it took 2 years to get back to 112. Then my 3rd child again instantly back to 112 then it went down hill after that. My 4th child I gain like 40lbs and after i got down to 125 after about 2 years I got down to 119ish lol. Then came along my last baby I only gain like 17lbs and so I was instantly back to 121. Then since then it has went up and down between 124 to 130.  So giving any day its between there. I am turning 30 this year and I am not having any more kids so I would love to be back to at least 115. It has really changed my moods and my self esteem. I hate my stomach that is the only part I wish was gone and tight. I went shirt shopping and really tried on like 50 shirt to buy like 3 I hated the way they fitted around my gut. 

I am trying but just need help I guess. I don't have the money to join any classes unless they are dirt cheap. I cant afford a gym. I do have a Wii and Wii fit and am thinking about getting a dance game and a fitness game but there are so many out there I don't want to spend $50 bucks and be a sucky game or fitness thing. So what have you guys found to help? Anything? What games do you use or like? Do you have a fitness video you use? What cheap equipment do you like and recommend like balls , bands, etc.? Any herbs or medicines over the counter you use and love? Any tips will be appreciated and I know I am not the only one fighting this battle so we would all like to know you succeeds and fails. I have had alot of fails!