How to hook up a solar panel to power Wilson Cell Amp.

Hey guys,

I've got this old solar panel my Grandpa gave me a while back. On the back it reads:

Power  >5watts
Voc       >22v
Isc         >450mA
Vop       >13.5v

And that it has a built in diode to prevent feedback. I've got 2 6v batteries, about 1/4 size of a car battery. (they're pretty standard, so I'm sure they would relate to anything you'd see lying around). I want them wired in Series for the full 12v. I've also got a female cigarette lighter adaptor. 

What I want to do is charge the batteries up with the solar panel and then power the Cell Amp with the solar panel too. I'd like them to both be there at the same time (solar charge and power the amp) if possible. I guess I want to know if I need some sort of voltage regulator, like the Burton one, and if this old panel will even charge up the batteries with only 5w and 450mA. Also, any estimates on how long I can power the cell booster on one set of batteries?

I'm sorry for the novice question. I've taken a couple electrical engineering classes and forgot almost everything :(. Anyway, I just don't want to do something wrong and explode my batteries or overpower my $$$Expensive$$$ amplifier.