Salesforce specialist for initial phone support of a migration and then ongoing development

We have a Salesforce app, which is live and in use.

We want to set up a Salesforce 'development environment' that our front-end developers can use for testing web integration (continuing to do this against our live instance is causing problems.)

Given the sensitive nature of the data, we need someone who can initially spend an hour or two on the phone (Skype, ideally) talking one of our programmers through this (literally, in real time.)

Assuming that this works, there will then be some ongoing development work for which you'd become the 'preferred provder.'

So, we need good spoken English, a Skype connection, and Salesforce app dev skills.