If a cell contains certain text then VLOOKUP

I've got a spreadsheet for past due accounts and each account is assigned to a particular collector. I'm trying to create a formula that will read the collectors name and depending on the name return a value from a different workbook. For example, if the collector is "Jessica" then retrieve info from Jessica's spreadsheet. If the collector is "Teresa" then retrieve info from her spreadsheet.

Thanks,
John

EDITED: Oops!! It's late and I just had an errant set of quotation marks. Here's the formula I used that works =IF($M2="Teresa",(VLOOKUP($A2,'[Teresa.xlsx]Top 50 Teresa'!$A$2:$M$51,13,FALSE)),(IF($M2="Jessica",(VLOOKUP($A2,'[Jessica.xlsx]Top 50 Jessica'!$A$2:$M$51,13,FALSE)),"")))

So what is your question - or did you fix it?