Question about Straight Talk?

Ok, I have a question/issue about straight talk....I use a lot of minutes every month and have been a customer of Straight talk for about six months now, and I still have straight talk, but I want a new phone number and the people at straight talk told me that they couldn't change my number for free, that I would have to buy another straight talk card in order to do that, and my straight talk service doesn't end until Jan. 2011 and I recently bought a samsung straight talk cell phone online for 49.99 it comes with 30 days of unlimited service(i was going to buy my card anyways and its already 45 dollars so it only made sense to me to go ahead and buy the whole bundle, phone and card for 49.99)I was just wondering if i want to change my phone fro mthe one i have now, to the one i bought, like transfer my number from my old pone to my new phone, will I have to use my unlimited card now, or can I transfter my number to my new phone and wait until my service ends and then reactive my phone when it runs out and have a newe number, or will it automatically start using my new card now? Ive tried to talk to customer service about this and they can't understand me and I can't really understand them...only serious answers please..thanks!