Python Tools for Visual Studio (PTVS) will typically automatically detect Canopy and show it as "Python 2.7 64-bit". You can check to see if it is detecting Canopy by selecting 'Environment Options' in PTVS. The path in 'Path' by default will be something like ...\AppData\User\Enthought\Canopy\User... If this is what it is finding, you should be set.
If the Python interpreter PTVS is finding is not Canopy, then it sounds like you have another version of Python installed. This is ok and there are two options.
If you want it to find Canopy automatically, you need to be running Canopy 1.1 or later and make it your default Python environment. To update Canopy if needed, go to Help -> Software Updates. Then to make it your default Python environment, Edit -> Preferences and click the button to make it your default. This has the effect of changing some Python-standard registry keys.
If you don't want Canopy to mess with your environment, that's completely fine, too. You can get the same effect by clicking 'Add environment' in the PTVS environment options dialog. The settings for a default Canopy install are:
Path: C:\Users\\AppData\Local\Enthought\Canopy\User\python.exe
Windows path: C:\Users\\AppData\Local\Enthought\Canopy\User\pythonw.exe
Lib: C:\Program Files\Enthought\Canopy\App\appdata\canopy-1.1.0.1371.win-x86_64\Lib
Note that the first two point to the 'User' environment whereas the last points into the core install.
The upcoming Canopy 1.2 release in a couple of weeks will include more complete integration with PTVS and Visual Studio that will automate this and remove the need for Canopy to be the default Python environment.