The most important thing is the folic acid which will be 800mcg if you've got it on prescription :) Iodine's a new addition to the preggo pill popping schedule. You don't REALLY need to take anything else, unless you've got low iron
You can save loads of cash(and pill swallowing) by just taking the prescribed stuff!! Maybe you could save the fish oil & pregnancy supplement for later on in your pregnancy, when you're feeling tired - I'm taking my pregnancy multi now at 19 weeks & it gives me a bit of extra energy.