I’ve seen the report on wizardistanbul on tv (yourope) > great idea, great job!!

my husband and I will be visiting Istanbul for the first time; we arrive on Saturday (Airport Ataturk) and would like to use the metro to our hotel (Yigitalp).
a) what metro station do we get off
b) which tickets are available, maybe even tickets that we can use for public transport during several days?
c) do we need to change money before we arrive to buy public transportation tickets or is it possible to use mastercard etc.

Thanks in advance for your help!