if you want to show the 2 Sum values in your form, add 2 Unbound textbox.
for the Total Payment, put this as Controlsource:
=DSum("PaymentAmount","PaymentTable", "PaymentDate >=#" & Format$(Nz([txtFrom],1),"m/d/yyyy") & "# And PaymentDate <= #" & Format$(Nz([txtTo],2958465),"m/d/yyyy") & "#")...