Mobile Invoicing App that syncs with "home"

[AMDin93101]

I have a mobile service-based business and I would like to invoice clients in the field electronically and swipe their card from one device, preferably a 3G enabled iPad.

Is there a solution for invoicing available, anywhere? Synchronizing with my "home" computer with the full QB 2011 application would make the most sense.

I would be satisfied with a single app, a grouping of proven software apps, a subscription-based cloud service or other creative ideas. I am a very small business but a moderate investment in such a system would not be out of the question.

As dreamy as Quickbooks Connect sounds, it's proven to be unrealiable and is not an option.

I am happy with SquareUp Merchant Services.

Please let me know what additional info I can provide to find a solution.

Thank you in advance.