I got my visa today. I only have 2 months on my ARC but it didn't seem to matter. I went to a Travel agent in Busan: use exit 5 Busan Station, take the first right, and then the first left. It is next to the bag shop that is on the corner in Texas St.

They speak a little English. It costs 50,000 won - I am an Aussie - and takes one week. Fill in the visa application beforehand, use a photo with a white background, and hand over your ARC. They will photocopy it. Pay upfront. Hope this helps.