Congrats on getting unit working.
Miele and other full sized rotary irons are much larger than this unit. Neither their roller padding or covers will remotely work.
Bosch, Siemens, Beatty Bros. Calor, Speed Queen, and countless others offered these table top rotary irons. Look around eBay or usual sources to see if anything can be had in terms of roller covers or padding.
Cover is easiest thing to make; just get a few yards of good cotton muslin and using old cover as pattern cut out a new one. It's just a length of cloth with edges folded over to make a casing for string.
Roller padding is probably knitted cotton, which is no longer made for domestic use. You can find it for large industrial ironers but that would be far too big for your purposes.
Knitted cotton padding cannot be washed so if it's soiled and has a really bad whiff you'll need to come up with something else. End is likely glued on with "ironer cement", but should come off if gently removed. You can try airing the thing out of doors for a few days, and or bung it into dryer on "air fluff" for ten or so minutes. That will help air it out and maybe fluff up the thing. You may be lucky in that the ironer wasn't used much and padding still has useful service life.