you have two choices here

1.) withdraw you 401k complete to fund your house, possibly the worst thing you can do with regular income tax and 10% penalty.

2.) take loan against your 401k at either half of your 401k or maximum 50K, with interest rate of 1~2% above prime rate. of course you pay yourself the interest. Down side is you have to pay off your 401k loan before you can change job.