Update and Modify Web Site

We are a new online retailer, we have our website created but our provider isnt being helpful with making some changes to our site, the site is in Wordpress and I have no idea what to do. Our site is [login to view URL] we are seeking help with (1) adding in a search function (2) Creating Sub Menu's for Products - drop down menu to show different product categories - can it be set up that when I add a new product and set the category it will be added to the specific product category page? (3) Add in Contact details so they appear top right hand corner of our web site (4) Change the setting for best product on the home page so that it isn't simply products that are loaded - I loaded a range of power banks and that's all you can now see. I am sure other changes will come up e.g. adding in PayPal etc