Voltage regulator question

Hey there

I have just built a mouse trap, two nights running and its managed to catch on both nights (believe in bacon). I was powering it with a 9V battery and two voltage regulators, namely:

http://www.datasheetcatalog.org/datasheet2/8/0ishsf7y9sp31h690e60g8gclc3y.pdf

The two regulators are in parallel, one for the ATmega328 and its components on a solder-less breadboard the other for the two tiny dc servos ( It got really hot trying to power both with the one regulator). The problem is now that the battery is below 7V the circuit doesn't run. The datasheet says for 5V to 18V output the input should be 35V, but I am not about to find a 35V battery at my local supermarket in the middle of no where South Africa. Has anyone got any suggestions other than a lithium 9V battery, so far I think it's my best/cheapest solution?

Any help would be great thanks!

The problem is now that the battery is below 7V the circuit doesn't run.

Arduino needs 7-20V to work, see hardware page

Considered a second hand car battery? ... will probably run for a long time ...

Thanks, I did I was just hoping that it would not come to something that size though.

I have found a pretty cheap wall wart plug though, I might just go with that for indoors and use the car battery for outdoors. Thanks again!