MS Access loan amortization Due date bi weekly...

I am using MS Access
PMT function to do calculation on loan amortization.
SchedPmt = -Pmt(IntRate / PmtsPerYear, MtgTerm * PmtsPerYear, MtgAmt, 0, 0)
I need to pull Due dates for payments relating which payment rate(number of payment per year) user chouse.
Something like this

   Dim Mths As Integer
    Dim PmtNum As Integer
    Dim PmtDate As Date
    Dim CumInt As Currency
    Dim SchedPmt As Currency
    Dim IntRate As Double
    Dim PmtsPerYear As Integer
    Dim MtgAmt As Currency
    Dim MtgTerm As Integer
    Dim PmtYear As Integer
    Dim PmtMonth As Integer
    PmtDate = Me.txtStartDate
    CumInt = 0
    IntRate = Me.txtInterestRate
    PmtsPerYear = Me.txtNumPayments
    MtgAmt = Me.txtLoanAmount
    MtgTerm = Me.txtLoanTerm
   Mths = CInt(Me.txtLoanTerm) * PmtsPerYear

    SchedPmt = -Pmt(IntRate / PmtsPerYear, MtgTerm * PmtsPerYear, MtgAmt, 0, 0)
    PmtYear = 1
    PmtMonth = 1
    CumInt = 0
    PmtNum = 1
Do Until PmtNum > Mths
…..
…….
…….. this part of function during loop  is ok, just  part for date making me trouble.

It should be something like bellow.

 If PmtsPerYear = 12 then
PmtDate = DateAdd(“m”,1,PmtDAte) ….’ Date will be increased  every fist of month
Else if PmtsPerYear = 24 then… ‘Date need to be increased  every beginning of month then every  15th of month.
Else if PmthPerYear = 26 then…. Date should be increased   every second Monday ????
Else if PmthPerYer = 52 then… Date should be increased every week(Monday)
End if
Loop


So I need to add Date for payments rate, monthly, semi monthly ;Bi- Weekly; Weekly monthly is not problem just those other ones.