Hi Amir,
Sorry for the delay in replying but I wanted to check that I had all the relevant information correct before doing so.
I am a little baffled as to why the examiner asked you whether you wanted to apply for your full licence yourself - I have never known this before. However, what's done is done.
You need to sign the certificate and send it, with both parts of your licence, within 4 weeks, to the DVLA, the address should be on the back of the form. That is all you need to do. You should not need any other application or any fee. If you need any other changes to your licence e.g., address, name or photo, or if you don't have both parts of the licence, then the above doesn't apply, so ask me again...
You do
not need your certificate to drive in the meantime. The certificate is not a legal document and is not considered by the police to be proof of entitlement to drive. If you are stopped, which is unlikely, just explain that your licence has been sent to the DVLA for exchange to a full licence.
You might like to take copies of your provisional and certificate, just in case
(although they are not legally binding).
I hope that clarifies the situation for you.
Emma