For curtains, have you got the hooks. If so then you should be able to figure out if they take a standard heading tape and get something made up. But then again do you really need the curtains. We've never bothered putting them up as they are fiddley and I tend not to wander around an awning without clothes on.
For the awning skirt, these are a generic item available cut to metre length from caravan shop, e-bay etc. Two drops are available, I think 55cm for caravans and 70cm for motorhomes. Buy the motorhome drop as it will tuck under the awning carpet which will keep it in place. Do not bother attempting a fancy cut-out in it to accommodate the Eriba step. I've attempted it and it really is a pain. Buy a cheap single step and use this to help put your awning up.

Colin