I use the Spokeman personal amplifier, which comes in a little case that can be set on the table, clipped on your belt, or worn around the upper arm like an iPod. It is used with the Hi-Gain 3-Way Headband Microphone, which can be worn around the back of the head, over the top of the head, or around the back of the neck. The places I know that sell them - Soundbytes and Luminaud - both have a 30 day, money back return policy, so if you think it might help, you can at least try it out first.
Good luck.
Lori
ABSD since 2003
North Texas