combining dates with nested if statements

I want to do a formula in G2 that states if E2 is between 2 dates then add E2 +85 and if it isn't between those two dates check if F2 is between same 2 dates. if F2 is then add F2 +85. if not, then leave G2 blank.

On top of that i want it to go to the next worksheet if it is the end of 2010 (i.e., put the same things in the 2011 worksheet so it carries on)
thanks

Something like this:

=IF(AND(E2>$A$1,E2<$B$1),formula+85,IF(AND(F2>$A$1,F2<$B$1),formula+85,""))

Where A1 and B1 are your dates

thanks i will try that i just am not sure if i keep the $ or not