I have a problem when i pull my a4 into 1st and 2nd, it just slips and won't go into gear. what is the problem and how easy is it to fix. when I put it in D or OD it was not slipping unless I put my foot in it.

I might try and fix or just by one.

 

If the tranny is slipping bad or has lost a gear then you probably need a rebuild. Not sure how many miles you have but if it is alot a tranny rebuild is a good investment.
Mandatory if you have lost gears.
Try to pull the tranny yourself if possible, you will save a bit of money.