Never ever swipe more than you can pay       

You should based the calculation on highest interest of 18% per annum.
Balance outstanding for the next month = [RM1500 + any new swipes] x 1.5% per month
I recommend stop swiping until you paid the 2nd RM1500 part to avoid paying interest on the new swipes.

Why is there a 34 months tenure when you will settle in full on the second month?

I not very sure how it works but I here is an example:

Since you will not be settling the outstanding balance in full prior to the due date, you may be imposed interest charges from the day you make the transaction. Please note this is not necessary the case (I don't really know - some reported they are only charges interest for unpaid balance after Due Date ). So assuming your card does charge interest from the day you made the  transaction.

Assuming you charge RM3K to the card tomorrow 18th July 2012, and you pay RM1,500 on 30th July 2010 and once again RM1,500 on 30th August 2012 (please note you got to add interest here to settle the debt in full, call CS to confirm the amount and add a few ringgit for payment to be cleared/captured).

18 to 30th July = 12 days
Interest = RM3000 x 15% x 12days/365days = RM14.80

1st to 30 August = 30 days
Interest = (RM3000 + RM14.80 - RM1500) x 15% x 30/265 = RM18.68

Also note, if you have Outstanding Balance after Due Date, you no longer enjoy the "interest free period" and as such any new transaction(s) with your credit card may also be imposed interest.

Anyway Bro, would appreciate is you could post here later the actual interest charges imposed after you settle in full your Outstanind Balance in full in 2-3 months time.

You may also want to read my article Credit Card Interest Rate - CC244