Welcome to Berkeley! Once you're here it will be easier for you to determine where you'd prefer to live. Having a young kid, you may prefer to live in flatter areas rather than in the hills, where sometimes there are no sidewalks, or you may actually like the peace and quite of that area... Sometimes google earth -street view can help get a sense of the streets and houses in certain neighborhoods..
In terms of the mortgage, it may be trickier, since presumably you have no credit history in the US, but to find out more you should talk to a mortgage broker you trust. Most real estate agents will be able to give you some referrals, or you can also choose to go to the lender directly.
Prices vary a lot depending on the neighborhood. trulia.com, or other similar sites, will help you with that. And, if you plan on coming to the Bay Area before you move here, ask a Realtor to drive you around. Ask to see a wide range of prices in different areas, and get a feeling for what you want to spend, and where.
It would be very helpful to know their preferences for proximity to transportation, shopping, etc. If they want to contact me directly, I can suggest lenders to work with, as well.
Prices will vary by neighborhood, but a 3-bedroom home is likely going to run them at least $650,000 on the low end in a safe neighborhood.
Cameron Platt, JD, CRS
Platt Inc. Real Estate