I'm currently going through the same situation..not a fun surprise..and I had to chase the threads in the pan..

I also used a M10 -1.50 bolt but I did not get a nylon washer so it's leaking (where did you get the right size nylon washer?..size?)
I ordered a replacement drain plug using Dorman 090-078 (ordered from NAPA# 7041049 for $2.49) which includes the plug gasket according to the picture. Not specified for Aveo I dont think, but the specs seem to match..will post an update once I install it..

It probably would have been easier to go with the nylon washer though