I concur. Temperatures into the low 40s are not a problem for the trees Anthony mentioned and Austin likely won't see anything that low until next December. Ficus trees are planted as street trees in San Fransisco! That city definitely doesn't have a tropical climate - I recall the kind of temperatures you experiencing now (highs in the 60s, lows in the 50s) in mid-summer. As I recall, 24th St. in the Mission District is lined with them - some over 100 years old. I think a bunch of them died in a freak cold snap in the early 90s when temps dropped into the low 20s, but other than hard freezes like that they can handle our weather here in Texas.
This was a pretty mild winter here in Texas, Dario. In Houston we had a couple of freeze warnings, and I recall some temperature dips down into the mid-30s. But with the exception of a couple of weeks, my "tropicals" (Black Olive, willow leaf ficus, macrocarpa, Fukien tea, texas ebony, etc) have been out of the greenhouse all winter. If you take your trees out now, the tree will be happy, as will your wife. Heck, she'll probably even let you buy some more!
Scott