Hi Gail, it's nice i could help. My name is Daniel and i collect books about Łańcut. Actually there are two books about families in Przedmieście. The book i quoted probably does not contain other new info about Jablonski's but it's huge source of knowledge about times in the past. The book is called "Ludzie z Nawsia" by Zbigniew Trześniowski. Bought it here http://www.instytutksiazki.rzeszow.pl/autorzy/p,47,zbigniew_...
where is still available. Contact info here http://www.instytutksiazki.rzeszow.pl/kontakt
ask if possible sending abroad, in case problems i can help.
Second book the same author is "Włodarze przedmiejskich łanów" which in the whole contains short genealogy trees (!) of many families from Przedmieście. You will find there Jablonski, Kochman and Kwolek surnames for sure. It's hard to find this book, i search online auctions and secondhand bookshops for it, it's still to buy by me. It's available in library though, i had it in hand about one month ago, heh.