Check out either http://www.greatschools.org or http://www.schooldigger.com as they are a couple of good resources on the quality of schools for any given address or neighborhood.
Concerning this particular address, I will spare you some effort and let you know that you won't find a house of this size in Walnut available for only $1200/month. This listing is likely a spammer, so be cautious in dealing with postings that look too good to be true.
Let me know if you need any assistance in finding a legitimate home to rent.
Alan Kurpiewski, REALTOR
CA BRE 01912043