1) It hasn't been passed yet....Only in the House.
2) IRS has indicated that amending would not be required, and they will have enough info in the already-filed forms to be sending out any additional refunds...when warranted......but it would take 6-12 weeks to be implemented......after the president signs legislation (IF it gets that far).
So, just move along with your normal tax filing. What will be will be,
____________*Answers are correct to the best of my knowledge when posted, but should not be considered to be legal or official tax advice.*