It'd be great if you can send the link to your store so we can detect your problems. If you are looking for apps to support your business, you can check on this list: https://apps.shopify.com/partners/autoketing
Not sure if it can help you out but some of them are free and you have a free trial. Good luck.
I guess you'll need a form builder with calculation capability. You can try this one: https://apps.shopify.com/powr-form-builder?surface_detail=form+calcuation&surface_inter_position=1&s...
It can support order forms to get quotes