How can I get this Powershell script to output various calculations?

Sample data:

AIS*00*          *00*          *AA*PPPPPP         *11*4165555555     *999999*0001*P*00123*00000020*0*R*>~
GS*PO*4161234567*4164567894*20100917*0018*0199*X*001111PQRS~
ST*150*12345678~
BEG*00*SA*8888888887**20140917~
FOB*PB~
DTM*119*20131002~
DTM*004*20131008~
N9*AH*4802028592~
MSG*Message.~
MSG*Message~
MSG*Message~
N1*SU*Company*8*123456789~
N1*BT*Name*8*1234567891234~
N3*1 Company~
N4*LOC*BB*ABC  DEF*CA~
N1*ST*D021 Loc*9*1234567891236~
N3*Street~
N4*Location*BB*ABC DEF*CA~
PO1**10*CA*12**UK*12345678912345~
CTP**UCP*12~
PID*F****ITEM 1 DESCRIPTION~
PO4*10~
PO1**50*CA*20**UK*23456789123456~
PID*F****ITEM 2 DESCRIPTION~
PO1**30*CA*14.03**UK*34567891234567~
CTP**UCP*14.03~
PID*F****ITEM 3 DESCRIPTION~
PO4*15~
PO1**10*CA*20.50**UK*45678912345678~
CTP**UCP*20.50~
PID*F****DESCRIPTION FOR ITEM 4~
PO1**100*CA*18**UK*78945612345678~
PID*F****THIS IS ITEM 5~
CTT*5~
SE*45*12345648~
GE*2*1234~
EFG*1*000025011~
AIS*00*          *00*          *AA*PPPPPP         *11*4165555555     *999999*0002*P*00123*000000021*0*R*>~
GS*PO*4167913211*4162475478*20100917*0019*0200*X*001111PQRS~
ST*150*2345678~
BEG*00*SA*8888888891**20130917~
DTM*119*20131001~
DTM*004*20131002~
N9*AH*1234034034~
N1*ST*D072 LOC*9*2471916380072~
N3*2700 NAME~
N4*CITY*QQ*ABC DEF*CA~
PO1**2*CA*40.10**UK*10060383002975~
CTP**UCP*40.10~
PID*F****DESCRIPTION~
PO1**20*CA*10**UK*21234567897450~
PO1**30*CA*11**UK*45678912345678~
PO1**50*CA*22.05**UK*1234567895458~
CTP**UCP*22.38~
PO1**80*CA*20**UK*4567894578454~
SE*40*50501231~
GE*1*1234~
EFG*1*000014052~


Sample script:

$InputFile = "C:\Programs\originalfile.txt"
$OutputFile = "C:\Programs\newdatafile.txt"

Function ParseText ($OutputFile,$InputFile){
Begin{
$poline,$totline,$total = $NULL,$NULL,$NULL
Set-Content $OutputFile $null
}
Process{
      Get-Content -Path $InputFile | % {

If ($_ -match "AIS\*1"){
      If ($poline -ne $null -and $total -ne $null){
      $Totline = "Total: `$$Total"
      write-host "This is Total `$$total"
            "`n$poline `r`n$totline" | out-file $OutputFile -Encoding UTF8 -Append
            $poline,$totline,$total = $NULL,$NULL,$NULL
      }
}
   If($_ -match "(SA\*)(\d{0,10})") {
      $poline = "PONumber: $($Matches[2])"
    }Elseif ($_ -match "PO1"){
        $col=$_.split("*") ; $total += [double]$col[2] * [double]$col[4]
  }
 }
}
}

if (Test-Path $InputFile){
     ParseText $OutputFile $InputFile
}


Desired Ouput in a new file:

PO Number:  8888888887 (this is the number next to the SA)
Item 1: UPC: (enter UPC code from the PO1 line),  Desc: (insert Description from the PID line),  Qty: (from the PO1 line)
Item 2: UPC: (enter UPC code from the PO1 line),  Desc: (insert Description from the PID line),  Qty: (from the PO1 line)
Item 3: UPC: (enter UPC code from the PO1 line),  Desc: (insert Description from the PID line),  Qty: (from the PO1 line)
etc
...add more items if there are more
Total:  (the total calculation for each PO1 data it sees for this PO1 ie

PO Number:  8888888891 (this is the number next to the SA)
Item 1: UPC: (enter UPC code from the PO1 line),  Desc: (insert Description from the PID line),  Qty: (from the PO1 line)
Item 2: UPC: (enter UPC code from the PO1 line),  Desc: (insert Description from the PID line),  Qty: (from the PO1 line)
Item 3: UPC: (enter UPC code from the PO1 line),  Desc: (insert Description from the PID line),  Qty: (from the PO1 line)
etc
...add more items if there are more
Total:  (the total $ calculation for each PO1 data it sees for this PO, ie  qty 10 x $12.00, + 50 x 20 and so forth...)  

etc..add more if applicable..


What modifications need to be made to the script in order for this to occur?

Thanks.