Hmmmm, you have a problem...
I would start by applying and squirt of good penetrating oil (WD40 does Not Qualify) to each one a few times over a day or so.
In the meantime, you can buy Left Hand drill bits at Ace or similar store. Punch mark the center of the broken screw (as close to center as humanly possible) and then start drilling with your new LH Drill bit. I would use about a 1/8" bit. You will likely find the screw will start turning out on its own as you drill but if not, drill it out completely, run a thread tap (most likely a 10-32 tap) in the hole and you are in Bussines.
The unbroken one may come out normal with the penetrating oil but if not, you have the LH Drill Bit. Right?
Patience is the key. Good luck.
P/S if that goes South, you can always take your little Dremil Cutoff tool and cut the end off, drill and tap new holes and there you have it.
Dennis & Carol
2003, 4006, 41' DutchStar,
Spartan, ISC 8.3L W/BanksPower - 2013 Honda CRV, BlueOx Baseplate, Aventa Bar & Patriot Brake. And the 04 Bird, Sunshine Car.