is about cancelling a contract on Three mobile.Can some one help me please?

Hi all,
yesterday, I had just brought my HTC touch pro(mobile) with $69 cap 24 months contract + $10 every month for the mobile and $20 -1Gb mobile internet.

I choose this plan is because i can get $650 credit to call.and 500minutes to people who uses three mobile.

Any way my purpose to get that much is because i want to use that to call internationally....to my mum.....and my wife

but today i found out there is a $100 limits on international calls.
and i had checked all the three mobile caps or even prepaid, they all have the same limit.

and right now i just want to do a $29 cap +
$28 for the same mobile..becausee it offers $150 credit...so that i wouldn't waste my money so much.

i just want to know will there be cancellation fees take place in my case?
and even though there is.....how much will i be paying and how are they going to calculate my cancellation fees?
Will i have to pay for the rest of the 24 mouths?
is there any thing i can do to fix that without costing too much?
what is the best way to fix my problem?
Is there ways that i can transfer to Vodafone?...because they don't have international limits..

i'm really confuse at a moment, don't know want to do.
I hope you guys can help me out.
today is only the second day i had started this contract.