I need to make some changes in my Shopify website

Hi I've been using shoptimized theme for over a year and l need to do some changes now. My website is [login to view URL] 1I would like to be able to add price description to products such as sqf, sheet or piece. Just like on the following link [login to view URL] /[login to view URL] 2) l would like to add calculator to product pages so customer can enter how many sqf they need and this calculator can convert it to the box quantity and add it to their cart by box quantity and box price. Some items have to be sold by box but I want to display sqf price and calculate for customers and also be able to show them box coverage quantity and box price. Just like on the following link: [login to view URL] [login to view URL] 3) I would like to make menu items little bigger on my website for desktop And mobile view without arrows showing below just like at [login to view URL] website. 4) I would like to be able to show collections just like the following link but I want it to be op- tional depending on the collection. Link: https: /[login to view URL] html. Of course mobile view and desktop view is different. You can check out their website. Let me know how soon we can get it done and how much would it cost to me.