Populating global vars from a regularly updated csv?

Hi - I’m looking to use some exchange rate data (relative to GBP) that needs to be up to date, and one way I thought I might be able to do this is taking a csv feed from yahoo and parsing it to update some global vars, using a cron to grab the csv and run a script every 12 hours or so…

http://download.finance.yahoo.com/d/quotes.csv?s=GBPUSD=X+GBPEUR=X+GBPCAD=X+GBPAUD=X&f=nl1d1t1

I get a csv formatted like this:

"GBP to USD",1.5815,"10/14/2011","5:55pm"
"GBP to EUR",1.1397,"10/14/2011","5:55pm"
"GBP to CAD",1.5977,"10/14/2011","5:55pm"
"GBP to AUD",1.5289,"10/14/2011","5:55pm"

The issue I have is that now I’m not sure what to do with it(!) - ideally I’d like to end up with some globals like {USDrate}, {CADrate} that return the relevant exchange rate. Any advice on how to do this would be really appreciated.