Alright so i've got some questions regarding my new clothing company

Im new to the whole trademarking / copyrighting thing, and need to know info on how/where to get things trademarked, and how much

First, Ive got my company name, what should I do with it? Anything? Its 'Heartcrush Clothing' What would be the better thing to do with it to legalize it, and how much is it gonna cost?

And with each shirt 'design' what should I do? Like my shirt designs, and logos, I figured I should trademark them, but i dont know where, who, or how much and what not...