If you're really desperate you can try this,K-Seal ST5501 Multi Purpose One Step Permanent Coolant Leak Repair. If it's only 8 oz so you can pour it into your usual spot.
On the not starting issue you need to be more specific, like will it turn over and not start or you get nothing when you turn the key etc. I've had my 07 G6 GT since new and 103,000 miles of care free ownership.
2007 G6 GT Emerald Green Metallic, sunroof, chrome wheels, continental dw tires, leather heated seats, in dash 6 cd player.