That would be a Class 10.9 bolt, which is the metric equivalent to a Grade 8.
So you'll need (6) M10 x 1.50 x 43(?)mm Class 10.9 bolts to for the frame mounting positions. That's a 10mm diamter bolt with a 1.50 pitch, and 43mm (I can't read the number, but it's 40-something) length. Probably not available at too many local stores. Try searching for a local Fastenal store or a Tractor Supply - they usually have a good selection. You may also be able to find the bolts at a local Mom and Pop hardware store, too. If all else fails, order online at Mcmaster-Carr.
Thanks. There is a local fastener store and fastenal so I shouldn't have problems finding this bolt.