Thanks for the answers!
I found out that the duemilanove has it's ow power regulater and may receive an input voltage of 6V-20V, so i wouldn't need an external one right? I don't care if my servo's receive noisy current.
Still if the battery start's to approach 6V the arduino tends to reset if motors start sucking power, with a relatively full battery it has no problems. To tackle this problem if found an old 10.000 microFarad elko, it has no date on it but it looks old.. Right now i have a 2200microF and three 220's. That doesn't seem to cut it if battery's start running low.
As for the switches, they are crude. I don't know what momentary means, but if they are pressed a contact is established, when released the contact is broken again. I ripped them from the control panel of a cd player. I already thought of using a led and a ldr with color lens to make a sort of sensor, but didn't like it and decided to go switches.
But then i read about seeker II a mini sumo bot and saw it uses an ir led and detector to make a close range sensor.. but i already started on the switchess o for now i think i'll use the switches and see if it works. And thanks again for the tip's!