Question about deducting an IRA contribution

The program said that I could get a deduction for contributing to a Roth IRA.  I currently have a Roth IRA, if I make the contribution right now, will that count towards this current tax filing?  And will that deduction be in the amount that I contribute.  For instance, if I contribute $5000, would that directly reduce the current amount it is reporting I owe in the same amount?