Hi. Can someone please help me on a date difference formula I wish to write.

This is the scenario: From a contract date field in my sql db I have extracted a date string from an alpha numeric string. This works as needed. Then having got this date string, e.g. 08/2004 (contract start date), I have added one year to this date this which reads as 08/2005 (contract end date).

This tells me that the yearly subscription has expired and needs to be renewed (as we are at the end of September now). Now my problem is how do I write a formula (or even an alert condition) that shows that any particular distributor needs to renew their subscription if one year has passed since the contract start date. The start and end dates are text strings, so how do I convert them to date strings? Please help.