take photocopy documents of your originals, go to a nearby notary public and have them attested. it will cost a few hundred rupees.
Send them by a courier like DHL or FEDEX. Im not sure about sending them in sealed college envelops. They are not that fussy about it. I sent them all my docs this way and they were all accepted by CAD universities. Official transcript means issued by an original college not through a third party.
or if your can do your first suggested step, take docs to your college and have them attested by a professor. if not possible, do my first step.