Perl Pattern Matching !!! Help

Hello

I got the below one from in one of this forums

For Ex: Loading File System Networking in nature

now i need to extract the patterns between the words File and Networking :

i.e. sample output: System

cmd used : cat <file> | sed 's/.File //' | sed 's/Closing.$//'

Actually i have the same criteria but i want to do it from a variable which has special characters ..

For Example :

$VAR=USING (FILE '/TEST1/FILENAME'5000)

From the above string i want to reterive the value between ' and ) in this case its 5000.

Any Suggestions will be helpful

Thanks

Rahul