Manipulating Pivot Table Data

Given myself the task of creating a spreadsheet to record the stats for my cricket club.
This is something I've actually been doing for a few seasons, where i have previously had a seperate document for each team, had a tab for each match and used vlookups to import the data into the yearly breakdown tab for that file.

As my excel skills have improved a lot through work lately I thought it was a good time to make some imrpovements and I now have one file, where the data is all entered into one sheet, and that is then pivoted into a 'batting stats' 'bowling stats' and 'fielding stats' sheet.
I used pivtos as they can be filtered very easily which allows me to filter the data according to season/team/competition/opposition/batting position etc.

One problem I am having is that the pivot table's are no good for calculating things like batting average and economy rate as I don't know how to, if its even possible, to enter columns into a pivot and am thus having to lookup the data from the pivot into a table at the side which then calculates things like batting averages / economy.

It would be much better if i could have a batting average column in my pivot, but I have no idea how to do this as to calculate batting average you have to combine other comlums from the pivot, rather than pivotting data from the data tab.

Any help would be appreciated.

Never mind, I have sussed it.
You can use 'calculated fields' to add fields like this.

Any other improvements would be more than welcome.
There are other things I'm having bother with but It would take me a while to explain...