Assuming your basement stays cool year-round I'd say move them back to a warmer area. Three weeks at 70*F is the common benchmark for average gravity beers (~1.050.) Leaving them in a cooler area will probably take longer, which you don't want considering it's an IPA. You can get away with that with beer styles that require aging but IPA's should be enjoyed sooner rather than later as hop aroma/flavor can diminish over time.
How long has it been since you bottled? If it's been a week or two go ahead and throw one in the fridge for 24 hours and then crack it open and try it. You'll get an idea of how carbonation progresses and it'll quell the antsy-pantsy nature that all new brewers have. If you can, try one each week so you can experience the process of carbonation yourself