The maximum amount of care expenses you're allowed to claim is $3,000 for one child. You do not qualify for the dependent care credit if your FSA (dependent care benefit account) is more than the expenses claimable for the credit.
If you had two or more children, the maximum credit would be $6,000 and you could claim an extra $1,000 (amount over in excess of your dependent care account with your employer) as a Child and Dependent Care Credit.
Any unusable amount in your tax-free dependent care benefit account, in your case $2,000, is added back to income as this amount is taxable.