Yeah, Then doubly so. Start with your realm forums, look for alliance guilds that are LFM. You might have to respec and learn DPS to get your foot in the door. Could also try finding pugs and start networking, get a feel for what guilds are doing what.
I found your armory. Decent set of gear. Most peices are 522/502 with a couple 496. You're in a hard spot. You'll probably have one or two upgrades from LFR, then you're running normal for upgrades.
Going for VP belt next week, absolutely busting my ass for tier pants next week (Spending 3/3 tokens after 'em). Boots will drop, or I'll get some form the 5.3 quest line. I don't think gear or ability is an issue (tanked 9/9 golds, I hope that's some indicator of ability at least).
Also got a 497 Rogue up for grabs. Gonna just go ahead and advertise both on my realm forums soon.
Tanks are the thing I've recruited the least in my experience. Maybe I'm biased being a Guild Master + Main Tank (and half a raid leader) but I'm very picky of tanks so I make sure I pick a good one and hold on to him. I recruited two tanks when I created this guild (early MoP) and haven't searched for a tank since then but I've recruited pretty much a lot of everything else. (Though I did have a DPS reroll into tankspec when one of my first tanks took a break for college exams)
3-4 tank fights are terrible. It holds guilds back because it requires you to have that many geared tanks. If it doesn't require alot of gear/skill then I would hate it anyways as a tank.
Finding a new guild as a tank is annoying but once you find the right home where you have a spot then you are set. One good thing (and sad thing) is that tanks are rarely replaced in my experience. Unless they are complete assholes or causing wipes time and time again, a guild will put up with a tank who is not the best.
I had my eye open for a guild that raided the hours I wanted and was recruiting a tank for almost a month before I found my current guild. They only carry 2 tanks so i knew I would be able to jump right in and prove my worth, which helped a lot as apposed to fighting an uphill battle to earn my spot. After being in the same guild for almost 2 expansions, I wanted to apply to one guild and stick with that guild.
Best advice I can give you is take your time and find a guild that matches your needs/wants. And get good and pumping out the DPS as a tank. Tank DPS is very important these days and every fight has some way to easily increase your DPS while slightly increasing your damage taken or requiring a little more coordination with your OT/healers. Being able to show that your DPS is that much better then another tank is just one more thing you have going for you.[COLOR="red"]