Buy a second 6V battery to put in series with the one you already have or a new 12V battery. If you try to use a switcher to step up 6V to 9 or 12 at 1.5A, the current draw from the 6V battery would be ~3A, so the run time would be short.
Im sorry I don't know what a switcher is? I'm sort of a noob when it comes to electronics.I'm not a complete noob, I know a lot more than the basics, I can solder and do small things like that, but I'm really bad at ic's and stuff.
Is there anyway to convert from 6v using a few resistors and transistors?
The websites are really easy to use, simple input the requirements and you'll be pointed to a datasheet which will have an application circuit one it.
Here's a simple circuit using a couple of transistors but you'll need to find a ferrite core and it's more complicated than using a regulator from one of the suppliers I linked above.
You can do it with a capacitor and DPDT relay that switches the cap so it is alternately in series with the batt. and in parallel with the batt.
If you switch at 1/2 Hz you need 1.5F for 1v P-P ripple. 5 Hz, 0.15F. 50 Hz, 15,000 uF. You're trading off relay contact life for cap. size.
I = C (ΔV/Δt), C = I (Δt/ΔV).
Three 4700 uF caps from Hosfelt.com is ~$1.50 total.