For exercise I have to recommend yoga and belly dancing. They're both great ways to shape a good body as well as trim the fat, increase satmina and flexibility and the belly dancing is fun while the yoga is soothing and relaxing. They are as intense as you want them to be and yoga especially has a wide variety of asanas (poses) and disciplines to experiment with and learn.
For some diet tips I recommend the following as a metabolism booster and fat burner:
8 oz. of organic,unsweetened grapefruit juice
1 Tbs. organic Apple Cider vinegar
1 Tbs. organic honey
Get the Apple Cider vinegar from a health store and make sure that it has the "mother" in the bottle. That's the live culture in the fermentation process that carries many of the benefits. Obviously if you have an ulcer or problems with acidic foods you shouldn't try this but otherwise it works great to detoxify, energize and burn fat. It also aids in the absorbtion of iron (apple cider vinegar is a pretty good source for iron anyway) and it aids in the oxidization of the blood. Three of those a day before (or after) meals is the recommended usage. I usually only have one or two a day though.
The HRT does affect the weight loss but don't stop taking it if your doctor has a good reason to have you on it. There are ways around it. From what I can gather from you, you're dealing with the stubborn belly fat that forms an undesirable "pooch." If that's the case; get thee to a belly dance class or buy a VHS/DVD tutorial on it. I have a love-hate relationship with the Belly Dance Twins Neena and Veena. I love that they are good teachers and have good DVDs. I hate that I will probably never look as good as they do. Oh well. Here's the link to their website.
http://www.bellytwins.com/shopping.htm
They also have belly dance for fitness DVDs. I don't know how that differs from the dance tutorials though. I liked learning to do the dance so that when I go out with friends I'm the one with the wicked cool moves. :-D
One more note about hormones since you're almost 29. In Traditional Chinese Medicine, we learn that a woman's body undergoes hormonal shifts every ten years or so. Therefore, even if you weren't using the HRT, or if you hadn't had a full hysterectomy, your body would be going into a hormonal flux right about now that might make you feel as though you were going menopausal. That's why you sometimes hear commercials for hormone therapies saying that the "symptoms of menopause can start as early as your thirties." I hate that phrase because menopause is NOT a disease with symptoms, it's part of the natural process of our lives. It's also misleading. There are some natural ways to help your body move through these transitions with greater ease and lesser impact on your feelings and your looks. Most of it revolves around diet and exercise. Check out this link:
http://www.tcmpage.com/hpmenopause.html
It's a pretty good brief on how TCM could benefit you and it includes a couple of recipes and names some of the key herbs used in TCM for women's health. Most of those can be found in a local health food store and are available as teas or tablets/capsules.
Good luck and let us know how you're doing!