Will assume you are NOT 59.5 and therefore neither your Roth IRA or your Roth 401k were qualified. Also, that you have only this one Roth IRA account.
When you rolled over the Roth 401k in 2011, you received a 1099R from the plan. Box 5 of that form that shows the amount of your deferrals to the Roth 401k. That amount is added to your amount of regular Roth IRA contributions for purposes of tracking your Roth IRA contributions. If you ever did Roth IRA conversions, this amount also needs to be determined, but will assume you did not have any prior conversions. If your Roth IRA value is more than these regular contributions, the remaining amount is earnings.
You fully distributed your Roth IRA in 2012. If your Roth IRA has earnings, you would elect to report a qualified first home distribution up to the amount of earnings, but not more than 10k. The result is that for the qualified first home amount you show, Form 8606 considers it a qualified Roth distribution, tax and penalty free. Your balance of regular contributions are also tax and penalty free. If you have more earnings than 10k, the excess is subject to tax and penalty. So first you must determine your balance in regular Roth IRA contributions and then you must complete Form 8606 correctly (or enter the required info into your tax program).
If you did NOT have any earnings at all, you would not even show a qualified first home distribution, you would save your full 10k for the future. Further, if you close all your Roth IRAs for less than your basis, the loss is eligible for a misc itemized deduction subject to 2% of AGI.
If you start another Roth IRA in the future, note that the IRS Regs do not require you to always have a Roth IRA balance. Therefore, your Roth IRA holding period would still be based on the year of your first Roth IRA contribution.
If you did Roth IRA conversions, reporting is more tricky if the conversions were held under 5 years. That's because you are limited to 10k in total for qualified earnings OR waiving the 10% penalty for not holding your conversions 5 years. So if you have conversions under 5 years, please advise.