Check out truck stops if you are on a road trip for a quality 12vdc to 115ac inverter.
To charge a laptop minimum is usually 100w....more output than an el cheapo brand to be found at radio shack. you also will be able to use it to charge phones and other things too simultaneously.
Take a look at the power supply block on your laptop cord....it will typically list a watt rating and go from there.
Don't skimp on cost. Undervolting sensitive electronics is a quick recipe for failure.
Look for clean "sine power" on the inverter label....otherwise your laptop will be nothing better than a wheel chock after a few short days.
Will be by the cb radios.
2x check that the one you are buying has a cig plug. Truckers offerings also can be hardwired ready....not what you are seeking for a quick road trip.
Lastly forget about Best Buy.....most that work in those big box stores couldn't find their own *** even with the help of a map. 4951