Unfortunately, the time to do that was before Ignite was installed and Digital TV was disconnected. It is possible to record the programming using a video capture device or DVD recorder but it may be too late. If you can still watch programming, just make sure the power is not disconnected as that will make the recordings inaccessible.
Another possibility is to activate the PVR on another account. The recordings will still be there. They may then be watched or recorded. Rogers will not reactivate your digital account on the same line as Ignite TV so it has to be someone with Rogers Digital TV.