the warranty is for the life of the bag, which coach determines to be about 5-7 years. i don't think that's totally strict though. however, the warranty covers the straps, stitching, and bindings (which is what it sounds like it wrong with your bag.) anyway, i would recommend taking it to your nearest coach store (outlet or full-price, it doesn't matter) and having one of the managers take a look at it...they can tell you what you can do or if you should even bother sending it in. they usually have a pretty good eye for it.
anyway. good luck! i hope your bag is repaired and everything is happy with it again!