Yelling. Nope. I wasn't even advising, just relating the path I took. Silly me, I learned a long time ago NEVER to advise a woman what to do, merely listen, commiserate, and at worst present a path I'd taken or someone I knew had taken. Anything more risks offense, and possibly worse, obligation.
All that said, I foolishly offer the following...
Danger's post got me thinking that there would be several advantages for you in replacing the internal SD, if you have one. A larger SDHC would meet your storage desires and also skip the issues that seem to pop up regarding the external SDHC. It would also allow you to set up the larger internal card and then simply make a complete copy of it in case the internal one got corrupted when away from home. You'd have to carry the duplicate card separately, and pop the case open to install it in an emergency, but that's not more complicated than powering off, running a thumbnail around the case, and swapping the card.
The other alternative might be to go Ken's route and install a third party reader program like KOreader, or two, hide your ebooks in a directory Kobo will blissfully ignore, and take a break from Kobo and their updates until they figure out enough to be worth being bothered again. AFAIK, you could still keep the Kobo software running if you buy books from them. The only downside is your Touch would sort of have the symptoms of Multiple Personality Disorder(or whatever "they've" decided it should be called of late, if "they" indeed support it's existence), but considering that they might be relatively benign personas that might not be so terrible.
Best of luck.