Man... just to be safe I'd stick it in the freezer for a couple days. Take it out, let it thaw for a day in a plastic bag, then freeze it again. That's the best way to kill any critters in yarn, and there's no reason it wouldn't work on fabric. The thaw/freeze cycle will wake up any bugs that have gone dormant--some bugs can survive being frozen when they're still in the eggs. The thaw tricks them into coming out of dormancy and the second freeze kills 'em. I also know some people who've bagged their yarn in a black garbage bag and stuck it in the car under full sunlight for a couple days. If they can't be killed by cold, they can probably be killed by heat.
All that aside, I would definitely contact the seller. Let her know that the fabric seems unharmed, but that her shipping supplies may need some attention. I'd hate for her to gain a bad reputation with other buyers if it's something she could have fixed had she known about it.