Hi I need some help!

I want to implement a new date picker on my site www.lakedistricthotels.net, I have put in the date picker on http://www.lakedistricthotels.net/newdate.php and also left the original date picker on. If I take away the old date picker and the code, the new date picker doesn't remember the dates when it goes into the booking portal and I don't know why.

Any help would be appreciated. I'm a bit stuck.