$filecontents =~ /.*?$blah\.([\w-]+)\(([^"]*)\)\s*;/;

#not really sure what $blah is holding but 
#the [\w-] can replace your [0-9a-zA-Z_\-] character class
#and \(([^"]*)\) is a greedy way of saying
#anything inside of parens that is not a quote.