I too would agree that for the interim we should use the P-3. I had the great pleasure of flying several during detachments to Kef' during the 70's and 80's and they were a delight to fly.
I wouldn't say they are/were as capable as the MR2 was (avionics and sonics wise) but the airframe was extremely nice to fly. I'm sure the Brown(e) brothers could do a deal with their good friend George W and get some of the ones from DM up and running soon.