What a pretty picture of you - had a quick snoop on your blog too and you look absolutely fab ! I don't know where you are hiding the 43lb you say you have to lose.
I think the gym will definately help. I had a lady on an IT course for the past two days, and of course as is inevitable when you get two or more women together, the conversation turned to diet and exercise.
She was saying that she exercises four days a week without fail, and that while she generally watches her weight (with a lot of cheating going on) she gets away with murder as long as she keep it up ("IT" being the exercise routine). At her age (probably around yours) I was the same - now I think the only way for me is something drastic like CD. I guess if I am honest, right now, though I want to lose more - the reality is that I am using it for maintenance.
I have been wading through some low carb veggie cook books my OH found for me. When I did LL, there were several of us who kept in touch, and the only one who stayed at her lowest weight (and is still there) is the one who moved straight onto the GI diet.