how can i boost the current from 2A to 6A while keeping the 19V from my dc-dc converter?

I have made a dc-dc converter to run my laptop of a 12V (car) battery using a lm2588 switching regulator. But my circuit isn't powerful enough. I can get a maximum of 2A out of the converter. Is there a way to boost the current to a maximum 6A?

The 2588 isn't powerful enough. You'll have to try the LM3488 and you'll have to use an external FET, because the switching currents will be quite high.

The 2588 just isn't man enough.

I'm in a similar boat, want to design a buck dcdc that can handle 2 amps from 7.2v lithium input to 5v regulated output...and before I even begin I know I can't magic amps out of nowhere :)
Web bench from TI/National's the tool to use. You need to know the limiting voltages of your input though.