Like Rice said, you can go to the 105 series 10mm studs, cone washers, washers and nuts. The hub has enough material to go up. But you will also have to have the axle flanges drilled out to accept new studs.
Toyota re-engineered the front and rear hub studs for the 105 series based on feedback Toyota received about the 80 series from use in Australia.
The hub as 2 6mm pins that locate the axle shaft. On mine I add 2 more 8mm pins to provide more strength. Again, the axle shaft will also have to be drilled out for these.
At least your's was in a good location.
I sheared my hub studs on Hurrah Pass in Moab in 2007 and had to drive all the back down in to Moab and wait for a rescue in the form of a used hub that CDan was able to bring from my garage in ABQ on his way up to Moab.
They sheared again on the Rubicon in 2009 and that's when I went with the upgrades. When I was wheeling the 80, I would carry a modified spare hub just in case. But the upgrades worked and they never sheared again.
Hope that helps.