Well, when it comes to getting results out of point-and-shoots, I can step right up with all these fancy-pants lens-swappin' dudes any day of the week. [img]/ubbthreads/images/graemlins/smile.gif[/img] (Just joshin', guys.) Keep in mind these tips are mostly beginner-level. If you're past that, good for you, and just ignore them.
Okay, here we go:
1) Get a tripod. No, seriously. Go pick up cans by the side of the road and cash them in or something but GET A TRIPOD. Otherwise find something to set your camera on. Then you can use larger shutter speeds and try available-light. If you've got a tripod, use it. I got a perfectly useable Kodak-branded tripod for $20 at Microcenter not long ago (it was an emergency) and while it's not the Rock of Gibraltar it holds the camera still. If you've already got a tripod, use it. Also, try setting the self-timer. Then the camera has time to completely stop moving after you press the shutter release.
2. For a point and shoot, the A40 is actually fairly sophisticated. Did you try upping your ISO-equivalent? You can go as high as 400 in manual mode. This also allows you to use available-light with not too long a shutter speed, which might help with the noise. Try different combinations - maybe you'd be better off at ISO 200 than at either ISO 400 with half the shutter or at ISO 100 with twice the shutter.
3. Okay, next. The auto white balance is what's giving you the odd tints: it can't make up its mind. Your camera has selectable white balance. (But no custom, more's the pity.) For a "normal" incandescent light bulb, you probably want the Tungsten setting. If it's a fluorescent bulb, then obviously you want the Fluorescent (or H) setting. If you're using the flash, you still want Tungsten, although you might try Daylight just to see what happens. Bottom line: digital cameras hate consumer light bulbs! If it's feasible, run over to Home Depot and get a daylight-balanced bulb for the lamp. If you do, try both Tungsten and Daylight settings.
4. You have a true manual exposure mode. Use it! Run the camera to its maximum aperture (f2.8 to f4.0, depending on zoom length.) Then experiment with shutter speed.
5. I know you said you couldn't spend any more money on lighting, but you can buy little self-contained slave flashes that fit in your pocket for $20. They're not DynaLites, but they can make the difference between getting a shot and not getting it. Here's an example:
Quantaray Slave Flash
If you get one, try bouncing it off the walls or ceiling in addition to just pointing it at your model. They're sort of harsh but they bounce okay.
6. Speaking of lighting, make sure the camera is using its Focus Assist Illuminator if you're using available light.
7. Even if you can't buy lighting, you can move light around. Get some white pasteboard and use it for a reflector. (Well, better yet, get a reflector, but this is the cheap bus.) If her walls are dark, try hanging light-colored cloth or paper on the walls to move more light to her. Hold one of those white pasteboards over your camera to maximize flash incidence. I'm sure you see where I'm going with this - take it and run with it.
8. If dark's the best you can do, do dark. Get some candles. (Don't burn anything!) Give her some pale makeup. Try shooting in B&W or some other special mode for a "noir" look.
That's about all you can do with a P&S, but you can get surprisingly good pictures out of one if you take it slow and find the sweet spot.
Now, as to posing: The best way to learn posing is to pose. Next best way is to look at lots and lots and lots of other people's poses. (That's why I have all these books full of pictures of nekkid ladies! Yep, yep, yep! It's all *educational!* No prurient interest here, no sir!) Short of that, here's sort of a nifty little thing:
This fellow has sets of cards with little line drawings of suggested figure poses. You can print them out, cut them up, and stick them in your camera bag. Stuck for a pose? Start drawing random cards. It looks a little silly, but it can help. The Internet Special is only $24.95. (Save your money and don't buy his "reports," though. There's nothing in them you can't learn here.)