Javascript will help, but if that's the only programming experience you have, it's going to be a busy month.
Yes, you can teach yourself php and asp in a month, but it will be very difficult.
Also, true expertise comes from experience that just can't be gotten within that short a time-frame. It is easy to learn constructs within a language, but common programming styles take longer to "settle".
All my knowledge about php is self-taught with the help of the php manual at
www.php.net. (that manual is reasonably good btw). So I can't recommend you any good books or such.
My advice: think of a pet project you'd like to build and go at it! That's the best way to find and overcome problems you'll likely encounter in your new job.
If you're really interested in PHP / ASP go for it!