Each new camera requires explicit support for its raw files—camera profiles and such, and Adobe only updates their current versions of software with that support. Elements 11 is too old to have updates that support your camera.
Specifically, your 70D needs ACR 8.2 and PSE 11 only can host up to ACR 7.2 so you’ll either need to pay for an upgrade from PSE11 to PSE14 which should work out-of-the-box, assuming your OS isn’t too old to be compatible, or you can use the DNG Converter 8.2 or newer and create DNGs from your CR2s and those DNGs will work in the older PSE 11 / ACR 7.x.
The latest DNG Converter is available, here: http://www.adobe.com/downloads/updates
The latest version of PSE is available, here—do the trial, first: http://www.adobe.com/downloads