netgear router N150..have extender about 40ft away in rv. router is in our trailer..

have N150 netgear in our trailer.netis extender 150mbps in rv about 40 ft away.person in rv is having issues getting a signal to hold for very long.should i get a stronger extender..if so, let me know a couple to choose from with price reasonable.i got a new router,ae type and couldnt get it hooked up so returned.very frustrated..please advise..