Hi there,
How quickly you can find a job in London depends on a lot of factors. If you aren't fussy about the kind of job you can probably find something very quickly, especially if you sign up with a few temp agencies. If you want to find work in a specialised area or a specific industry or profession it might take longer.
As others have said, the cost of living in London is high, expect to pay around £200 p/w in rent on a one bedroom place in the inner suburbs. If you want to know about the cost of groceries, have a look at some online supremarkets eg tesco.com, sainsburys.com
My husband's from Southern California too - Orange to be precise - where are you from Cali?