1995 BMW 540i

I have a 1995 BMW 540i. It's been running fine , although it took longer and longer to start lately. I blamed it on the weather around here (single degrees) and just ran it w/o turning on the radio or the headlights so the battery stays charged. Got cold last night, now it's not even turning over. I called AAA and they tried to jump it from under the hood, but i don't think the jump was strong enough. The car would act like it's about to start, but it wouldn't turn over. Any help, tips, or suggestions about gettin this bad boy started would be greatly appreciated. My hands are starting to freeze...