Roger, depends on current req'd at the stated voltages. 12 volt will be low? (straight off the battery, doh!). The 5 volt will be a little higher, but there's an easy solution. A very easy-to-make, regulated supply using either an, LM7805, 1 Amp output, or an LM317 or 350 for higher currents.
L.
ps. They ALL must be adequately 'heat sinked' tho!
pps. Hope you can make them out. Darn jpeg compression..
ppps. They are "ALL VOLTAGE ADJUSTABLE". see LM317 info.....If you need the larger sized pages, PM me..