Online Racing Championship spreadsheet-changing points to positions

Hello all,

I host an Online F1 Championship every weekend, and I currently log all of the race results and points totals in a spreadsheet.

Here is an image; http://imgur.com/Bl0PwBh

Basically, on the right hand side you will see a Positions/Points table (1st = 25, 2nd = 18 etc) and what I do, is I put in 25 for the race winner, next to their name on the relevant race they won. I want to be able to change this so I can put in everyone's positions instead of points (1st instead of 25 etc) but then the totals on the right hand side to add 25, or add 18 depending on the position I put in the cell. Is this possible?

I tried "=IF(A3<1>""AA3+25)" but had no luck.