There are plenty of great places to hunt in your area! Those were my old stomping grounds. Do yourself a favor and go to the next meeting of the Santa Clara Treasure Hunters Society. http://waipahuhaole1.tripod.com/treasurehunters.html
As a matter of fact, you should join the club. Not only are they a great bunch of gals and guys, membership gets you the MD permits you need to hunt the Santa Clara county parks and the San Jose parks, so its a steal. The club, due to its long standing cooperation with the city, county and law enforcement agencies, gets the permits at a fraction of what you'd have to pay on your own, making the membership free.
When you do go, give them all my regards and tell them I miss them.
I am not sure if you are still active or not. I just moved to Milpitas as well and I am wondering if there are any good hunting spot in Alviso. Have you tried that area yet?