I don't know what an IRRA account is, what do you mean?
Assuming you mean it was a traditional IRA with a pre-tax balance, then all traditional IRAs are considered for the pro rata rule.
If you had $1500 of pre-tax funds, contributed $3000 of non-deductible funds, and converted $3000 to a Roth IRA, then 66% of the converted amount is after-tax and 33% is pre-tax, so you will pay income tax on $1000 of the conversion. That leaves you with a balance of $1500, of which $500 is still pre-tax and $1000 is after tax (has a basis). This is all recorded on the form 8606 that is generated with your tax return.
