PR is animal protection activists' cant and translates: a set of measures, active search for new home for an animal. These measures include: print and post paper ADs; publish in newspapers; place on Internet forums, bulletin boards, social networks etc.; call round friends and colleagues; and so on.
See also How to find the animal a new home
Who is the guardian
The guardian is a person who is voluntary committed to one or more stray animals and feels absolutely responsible for them, the primary contact for all related issues.