Welcome aboard, while not many here may have a Coromal pop top it would depend if the screen section is removable or not, some are velcro panels which makes it easier, if not then you will have to remove the whole vinyl skirt, either way take it to a canvas w/shop, place that makes tarps, auto trims etc and they can fit new screens of a weight that suits better..... A caravan place will just out source the job and charge you for the priviledge.
As an emergency repair for small holes slap some sticky tape over the hole/tear give it a liberal dose of aquadere with abit of tape over it again, when dry the tape will fall off and the hole is closed off, works for a fair while and keeps the bugs out, kept dry is best though.