I'd bite the bullet and get the highest quality down sleeping bag you can afford. It will last a lifetime if well-cared for, and (for a 20-25*F bag) will probably weigh no more than a couple ounces over 2 lbs. (at least that's what you should aim for--if you're big and tall you'll need a heavier bag). Consider it an investment. Western Mountaineering, Feathered Friends, the Marmot lightweight line (Hydrogen or Helium), Montbell are all good (note that Montbell bags run small, as does their clothing).

As for a down jacket, I personally don't like having all my insulation eggs in one basket, so to speak, so I use a synthetic puffy jacket instead. I may end up changing my mind, but I haven't yet. Fleece is fine, too--a bit bulkier and heavier, but a lot cheaper--you might even find a nice warm fleece jacket at a thrift store. By the time you put together your base layer top and bottom, a warm intermediate layer (like 300-weight fleece) and your rain gear, you should be quite warm. It's all the layers together that do the job! Don't forget warm hat and gloves!