Prempro may be just the thing you need then. It will help with hot flashes, depression, dryness, all the fun stuff.

If you periods are getting closer together it's nearly always a lack of progesterone. The hot flashes are caused by lowered estrogen.
As far as the aspirin goes, I'd switch to naproxen sodium. It's brand names are Aleeve or Naprosyn but I get the cheap Walmart generic. Start taking 550mg a day about 2 days before you expect your period (I know it's hard to predict sometimes) and keep taking it until your period is over. It can reduce your bleeding and clotting by more than 50%.
If you find your periods become more irregular or heavy than they were before you started the Prempro, you may only need progesterone and not the estrogen that is in prempro.
Another good alternative to control cycles and bleeding is birth conrol pills. This is what I'm going to try now as I can't seem to get my period to stop. I'm 43.
Good luck to you. Sometimes it takes a good 3-6 months for things to get more stable. Sometimes it takes trying a few different medications to get just the right one. Hang in there. I know it can be very stressful when things aren't under control but try not to worry. You're just going through a natural process that hopefully will be over soon.