first, you can focus with the hood/filters attached, provided you cleaned out the Agfa "lubricant" and the focus helical turns smoothly.
30mm (Isolette) and 37mm (Record) push on type filters and hoods can be had for a few bucks on swap meets or at the usual online auction site, at least here in Old Europe. Using these push on filters and hoods for me holds one advantage: Regardless of the maker of the hoods/filters, you should be able to "stack" the hood on any filter of the same size. At least that is my (limited) experience with the few filters and hoods I own. This is nice because with these old cameras/lenses it is recommended to always
shoot with a lens hood on, not only when shooting against the sun.
As mentioned, most post war models of the Isolette take A30 filters and hoods. The original accessory hood from Agfa for the Isolette looks like the one in the link below (price is on the high side).
I don't know if there is a similar plastic hood from Agfa for the Record (A37), I have never searched for it, because I use a generic metal hood (maybe from/for a Voigtlander?) that works just fine for me.
Hope this helps,