Soften the rear suspension and remove any rear sway bar you have. Alternatively, stiffen the front end.

The rule of thumb for handling... To induce over or understeer, or correct either, you simply soften the suspension at the end you want to grip, or harden the suspension at the end you want less grip. This goes for almost all suspension adjustments, spring rate, shock oil, sway bar thickness, camber.

You should definitely reduce front toe-out if you have a lot, but increasing rear toe-in won't help much. Consider lowering the car when running on asphalt, and increase rear droop.