Calories, calories, calories.....?

hi, i have managed to lose 3.5 stone in the last couple of years and have now regulated at 9.12stone... i dont diet anymore i just balance it out and have a bit of what i like in moderations... even though im losing weight i am noticing fat collecting around my stomach, thighs and bottom and alot even though i do walk to and from the station, i dont go to the gym however... hate gyms! i just wondered how to stop the weight collecting on the bottom half of my body as the top half seems to lose it... my chest is getting smaller and smaller and top part of body kind of skinny then the bottom half is filling out - not good.... what to do - also i generally eat around 1,500-1,700 calories a day just what im comfortable with etc; but yesterday i actually had a bad day and had around 2,700 calories :( - we all have days like that but i wanted to know can you put weight on like that even if i keep the calories to 1,500 most days, but say two out of seven i go up to 2,000 or over, will you gain weight that way??