American living abroad. What part of my savings is eligable for a Roth and can my wife start a Roth?

[Guest brapa]

I am an American living abroad. I have two questions.

First: I understand that I cannot use any untaxed income to set up a Roth IRA. With my income being below the $80k foreign earned income exculsion for the forseeable future that means I cannot use it to set up a Roth IRA. However, before leaving the states I had money in a savings account. I would like to use this to set up an account.

It, however, gets a bit murky because when I initially went abroad I took more money than I ended up needing to get settled. That was then eventually sent back to the states and deposited in my account. I have also deposited savings earned abroad into the account.

Can I use my savings and if so how do I establish the amount of savings which was earned in the US and the amount that was earned abroad?

Second: My wife is not an American citizen. Can she set up a Roth if she has income earned and taxed in the US? If she can't set up her own, is there any way we could set up an account together so that I could contribute an additional $3000 per year?