Okay my friend, I have your definitive answer.
First, I assume that you have taken care of the contents of B4 and C4, and that you are changing D4 by typing in W or L directly into the cell.
For C1 use the formula from the answer directly before mine, it is spot-on.
The formula you want for cell E4 is:
=IF(D4="L",C4,IF(D4="W",B4,""))
(ignore the three dots after the formula Yahoo Answers is putting them in!)
The formula you want for cell A5 is:
=IF(D4="L",E4+2,"")
These formula's check for L or W (or both depending on the formula), and do the business, and if it is neither L or W, but nothing or something else, they clear the cell.
This should sort you out.