OK. You're basically doing what I'm doing then, except you're expecting customers to come to you instead of doing it the right way. Let me highlight the flaws here and pray that you understand.
You run the business out of the home. You do the majority of the work out of the home. BUT, you don't want customers to come into the home, because... it's a home, not a business. The problem there is that you still need a place to interact with the customer... somewhere where they can show you what's wrong with their computer... somewhere where you can go over paperwork, estimates, invoices, contracts... somewhere where you can accept payment... where the customer can WATCH you swipe their card. How do you accomplish that without letting the customer into your home-based shop?
You go to the customer!
Just because you're mobile doesn't mean you have to stick around for hours and do all the work in their living room. You show up, do a quick run-through with the customer to make sure you're addressing all their issues, you make sure the customer understands your fees and contracts, fill out all the paperwork, and then haul their computer back to your house to do the work! Once the work is done you schedule a drop-off, you give them their equipment, the invoice, and accept your payment.
BAM. Done.