I am happy to dispense free help and advice, preferably in forum discussions so it's open for everyone, but also by private message if it's more sensitive.
I don't run my own store but am a hired gun; you can pay me to troubleshoot emergencies, write new addons, install or adapt existing addons, migrate your store from an earlier version, connect your store to other systems like stock management, accounting, ebay and so on.
As well as the addons published in apps.oscommerce and linked below, I have other solutions that are commercially available, including payment methods and stock/finance integrations.
Brockley is an area in south London. I lived most of the last 30 years round the corner from a pub called the Brockley Jack, wrongly believed to be the name of a local highwayman.