Conditional Formatting - Using Date and additional value

I'm trying to use a conditional format to change cell B7 either red or yellow

B7 Value: 4/17/13
C7 Value: 6 - (This means 6 months from the above date we have to turn it back in.

So I wanted to make cell B7 Red when we exceed 6 months from original date and I wanted to make cell B7 Yellow when we are 1 month prior to the total time (6 months).

If this is not possible my other option is to have the dates in cell K-Q:7 change colors (as stated above) using the values in B7 and C7.

I would really appreciate someone's help, I can't find an answer online because I'm using and extra cell that lists the months total we can have an item out


Thanks