Get out of Marymount Station (Circle Line) from Exit A. Face north and walk 400 meters. You should walk pass an overhead bridge, then Shunfu Road followed by a second overhead bridge. Cross the second bridge and Marymount View is there... at the junction of Marymount Road and Pemimpin Drive. Just opposite Shunfu Estate.
To see the area on Google Map, click here: http://maps.google.com/maps?hl=en&q=marymount%20view&um=1&ie=UTF-8&sa=N&tab=wl
How to get here from other parts of Singapore (thanks to Garry): http://gothere.sg/directions#Marymount%20View,%20Pemimpin%20Drive: