Decimal places in "calculated" field

I searched through some other posts and can't figure out how to apply the answers to my situation.  

I have a detailed form.  Three of the fields towards the end of the form are:  Subtotal (which adds up 8 fields above); Plus5 (which calculates a 5% cushion on the Subtotal field); Total (which adds together Subtotal and Plus5.  

These calculations and formats (decimal places, etc.) are correct and I'm not having any trouble with those.

Then I have a Summary field which pulls in text and data from all the above fields that looks like this:

Conference Registration $ 500
Lodging $ 251.56 X 3 = $ 754.68

Out-of-State Total $ 1254.68
Plus 5% (In-State Only) $ 62.73400000000001
In-State Total $ 1317.414

This is a custom script that looks in part like this:

event.value = "Conference Registration  $ " + this.getField("ConfRegFee").value +

"\nLodging  $ " + this.getField("HotelCost").value + " X " + this.getField("HotelNights").value + " = $ " + this.getField("HotelTotal").value +

........ +
"\nOut-of-State Total $ " + this.getField("OOSTotal").value +
"\nPlus 5% (In-State Only) $ " + this.getField("Plus5").value + "\nIn-State Total $ " + this.getField("ISTotal").value

I have two questions.  

1) How do I get the Conference Registration line to show in the Summary with 2 decimal places?

2) How do I get the Plus 5% and the In-State Totals to round to 2 decimal places?

I'm thinking it has something to do with not formatting the fields as $, but as numbers with 2 decimals....  But, I can't seem to get that to work either..

Any assistance is appreciated!

Thanks,

Ruth