Filtering/Replacing Problem

Greetings
I'm not new to Excel, but I'm far from being on the same level of most of you. Here's my problem:


A B C D E F
11/13/2009 0:55 METAR KORD 130055Z AUTO 17016KT
11/13/2009 1:55 METAR KORD 131155Z 16017G21KT 10SM


I'm trying to average/ sum hundreds if not thousands of rows of data like the ones above. The problem is that the data in Column E sometimes contains the text "AUTO", when it does, the value I need to work with falls under Column F. Is there any way I can set up my spreadsheet to remove the AUTO and replace it with the value in Column F? Or am I missing something, is there an easier way to work this? Thank you in advance. GR