From doing a bit of research on the internet

it seems that: know where your milk comes from; if the cloud travels to you, stop drinking milk for a while. It is also, a good idea to eat less, because most foods will be absorbing radiations, some foods absorb more than others - I'll do some research and tell you what I find out there- and you might as well use iodized salt and sea salt, and also supplement with some natural sources of iodide ( often from sea algae and unfortunately laced with chemicals, chemicals used to break down oil spills and thus, sea foods are at this point possibly dangerous so no sea food from the Gulf...)

 Stay indoors, windows closed when the weather is wet,  on a clear day and a nice wind  the cloud will move away quicker.  Also, radiation move quickly with diffusion and thus without precipitations the radiation will not linger.

Children are way more sensitive to radiation; their cells are dividing quickly and thus can multiply and replicate a mutation very quickly.

Get involved, close the nuclear power plant next to you. Remember, Tokyo is registering high radiation and it is 150 miles away.

These are the precautions I plan to take with my family: doing something is better than doing nothing.