help with simple UPS 12v

dear sirs,

i have little knowledge in electronics but i in need for a simple ups 12v something like that :

http://www.turboimagehost.com/p/15293607/untitled.JPG.html

its simple UPS (+9V , +12v) load 1.5A max.

power on , charge battry , +12v,+9v on
power off , battry feed for 7 min , 12v,9v on
after 7 min , ups is off

i need values for Q,C,R1,R2
if you got a better i will be very thankfull

thanx