1. Create a formula:
IF {Installment date field} IN CurrentDate to CurrentDate + 365 THEN {Installment amount field}

2. Create a Running Total on the formula that was created in Step 1
3. Place the Running Total in the Group Footer, or Report Footer if it is a grand total.
4. Preview your report.

Please note: The formula syntax listed above is an EXAMPLE ONLY. You will need to use the actual Gift Installment Field when creating the formula.