Text replacement in php script using regular expression

I have a php script ("[login to view URL]"), which includes various functions and other stuff. In this main script, there is a function: *Function Get_currency_data(){* *$choix="USD(**Y,1, USD ,U.S.D,Dollar americain,dollar amairicain,Etats Unis ,"Equateur, Porto Rico,Panama, Congo Daimocratique, R.D.C, Za hire),GBP(Y,2 ,GBP ,G.B.P,Livre sterling ,"livre anglaise, paounde,livre sterlinegue",Royaume Uni ,"Angleterre, Et cosse, Pays de Galles, grande bretagne), etc..)";* *$rates= ?USD(1.3513,1.2658),GBP(0.8695,0.8163),etc ?* *$currency_data=array($choix,$rates);* *Return $currency_data;* *}* $choix and $rates values are generated from csv file. I need a script that will open the mainscript file, and replace the $choix and $rates by new values generated from the csv file. I need the work done by a coder proficient in regular expressions.