Best snake for bathroom drain

I have stubborn drains on both lav sink and tub - bought a 25' hand snake today, cranked the heck out of it on the sink - still no good. Got maybe 6-8' inside the pipe under the floor, still getting resistance (and a sore shoulder). Tried baking soda and vinegar - got a good show, but it sat in the drain, even after covering it up (it was worth a shot).

I'm thinking I need something more powerful - any advice on DIY style to buy (ideally something to hook to a drill)?

Thanks as always.

http://www.terrylove.com/images/power_spin.jpg

Electric drum snake will be the best option.

Keep the cable clean inbetween uses and do not use chemicals prior to using the snake; it will destroy the cable.