Back when we first thought of git, I had left my laptop on over night trying to copy the google SVN to a local git and it never completed successfully... now you're experiencing the opposite sort of problem.
Goblin Hero had asked if I had an archive of the SVN repo that he could seed the project with. If your local SVN folder has all the data necessary, then this would be an option. One upload instead of all the revisions... keep in mind some of those revisions affected thousands of files at once, like the couple times we modified the cardname.txt structures....
Barring that, is the SVN history critical? I don't think so... if the history were dumped to a text file, and included for historical purposes, folks could read everything that's been changed since revision 0, IF they needed to. It would be nice to be able to jump start the revision numbers, so that there's no overlap... then how do the git revisions get numbered when merged with the SVN?
Forge is really almost a different project than when the google SVN was started.
No bandwidth issues, cardforge.org is unlimited now, but it's just not the fastest responding server....
Seriously, on a going forward basis, slightlymagic.net is plenty fast, downloading what did succeed, was lightning fast. When I would update from google, I'd get a couple card files per second listed. From here, they were scrolling by quicker than I could read them.