It is better if I could know your website, then there will be more useful suggestions for you.
However, I should tell you that Shopify has a lot of downvote for these:
-The Apps. One of the best & worst parts of Shopify. There are some really good apps, and then there are some apps that are slow and bad. Some seem to be overcharging for features that should be standard in my opinion. Want a intelligent filter menu? $15 per month. The cost of some of the apps are in no logical relation to the price of shopify. The basic plan costs $29 per month, and a filter menu costs half of that.
-Pricing. You can see lots of complaints about Shopify Pricing.
-POS and Barcodes by Shopify are horrible. No real world use for me. First of all the Shopify POS seems to be geared towards a small retailer who sells like 10 times per hour. It lacks basic features like reciept printing on a printer other than these small restaurant-like reciepts. I want to print a nice Din-A4 reciept. I really would love to use Shopify POS in our stores, but seeing how slow it is, that really wouldn't work.
You should consider a better POS and Inventory option such as this Magento ERP. There are many upvotes:
-Customizable Extension: Well. It is easy to customize, you need a custom Inventory which can track inventory, record sales, and have reports? Why not ERP for Magento.
-Pricing: One time payment. Why not?
-POS and Barcodes is far much better than Shopify. Login takes 30 seconds, no more to load up to 100000 SKUs. Offline mode available. I checked enough POS to confirm this POS is one of the quickest POS systems.