Got a notice from my ins. co that there is a sag in roof and it must be replaced by 5/2012 or they will drop policy. Can I still make claim b4 that?

The sag in your roof may not be a covered item.  Insurance companies pay for damages to a roof caused by a storm, winds, falling objects.  If the sag is simply a maintenance issue, or caused by a roof that is old, the insurance company would not be responsible for the roof. Insurance is for sudden & accidental loss or damage, not simply to maintain the home. Since the company contacted you regarding the roof, it is most likely they feel it is not a loss they would pay for but rather a maintenance issue.

I would suggest that you contact a roofer and ask them to check out the sag and see if they can determine the cause.  If it is due to age, I would recommend that you get the roof replaced before May of next year, since it will be very difficult to find a replacement insurance policy when you are non renewed by the prior company.