Search contact means of purchasers / optimize google adds for my website / Marketing on internet

Hi, my name is Danny Ni from China. I run a export company which sells Chinese dim sum, dried fruit&vegetables, candies for kids and some kitchenwares to Europe, USA, Canada and South Africa. I'd like to hire a freelancer partner to help me find out contact means of purchasers for my products. The contact information should contain name, title in company, email add and phone number of the key man. And if it could be, I also hope that you could optimize the approach of google adds for my website after I had finished building it. Also, I would be glad if you had other advices to optimize my marketing on internet and my linkedin. This job could last a long time if your help would be sustainable.