You would need a 5-1/2 room apartment. Verdun is closer to the city core than LaSalle is.
Here's a link that I posted on another thread - Montreal Apartment Living -
Neighbourhoods
Some of the duplexes in LaSalle can be iffy; I lived in a couple and the noise in them really travelled.
Here is a link to
Kijiji rentals in Montreal.
You can certainly look on Craigslist as well (link on the Apartment Living site) but beware. There are a few scammers on that site...