Pick up a double quoted substring

I need to pick up a qualified path name of a file inside a string. For example "C:\Document and settings\user\test111.txt" on Windows or "/tmp/mydir/test111.txt" on UNIX.
The sample input string may look like
...some data......"C:\Document and settings\user\test111.txt"....some other data......"/tmp/mydir/test111.txt" ..........

What is the best way to do this ?
I tried to use tokenizer. But I don't know how to specify " (double quote) as the delimeter.

You use \" to match a ".