But you will need to make sure both your Canadian CPL and Canadian RT license is valid
You will receive the renewed RTR P for another 5 years
The Canadian RT is valid for lifetime.
The second part is not correct. Your renewed RTR(P) will be valid only till the date your Canadian Aviation Document Booklet is valid for. Even if you apply with a freshly acquired booklet, your RTR(P) will still be valid for a period which is slightly less than 5 years (the validity period of the new booklet).
The best course of action would be to clear Part 1 RT examination and apply for a 20 year RTR(C) for Rs 5000/-.