My friend had some paper advertisments for his turkish restaurant. I said:

Ofisime getireceğim.

He corrected me saying I should use koymak (i.e. instead of getirmek)

So I´m a little confused.

I´m guessing one would mean "I will bring them to my office" and the other would mean "I will put them up in my office". Maybe he was just making sure you would put them up and not throw them in the bin after bringing them to the office

JQN is right.

Koymak is better than getirmek. If your friend has some paper advertisements and you want to help him by putting them up in your office, you should say ´´ Restoranının reklamlarını ofisime koyacağım.´´

If you say that ´´getireceğim´´ , your purpose does not be clear. Maybe you will bring them to your office and put them on your table with other papers and no one will see them.  Of course people will understand what you mean, but ´´koymak´´ is the best choice.