60 isn't terrible although it will take a bit longer to carb/condition at that temp. I used to keep conditioning beer in my basement which was about 62-64. It took about a month or so for it to condition out.
If the temp is higher during the day then I wouldn't worry too much about it. A quick idea I have though is to put water bottles full of warm water in a box with the beer. You'd have to keep changing the water out so I'm not sure, at 60 degrees, if it would be worth the trouble. Maybe try it with a thermometer in the box and see what the temp does over time.
If I think of anything else I'll come back and post it!
You can put them somewhere where the temperature doesn't fluctuate as much- like in a cabinet, or a closet, or in a place where it's warmer most of the time like on top of the fridge.