How to get my itunes on my new computer?

For years I've had my itunes on my moms computer. Several months ago I bought my own computer. I haven't moved my itunes yet. My mom was having computer problems and had the computer completely cleared. So I'm pretty sure my itunes is gone from that computer. I have all my apps, songs, contacts, pictures, etc. On my iphone right now. How can I get what's on my iphone onto my itunes on my new computer?

Just download the Itunes again on the pc. Then get a cable to connect from your iphone to the pc. Usually the songs you purchased can be redownloaded to the pc and won't be charged as long as the account is the same

You may take a look at this step by step guide, it's about how to transfer files from iPod touch/iPhone to computer iTunes, it supports Apps, Contacts, Songs, Videos, Photos, Playlist, Notes, Games, etc. Data files. Easy to understand and works pretty well for my iPhone 5.