I can honestly say there is no substitute for getting your packaging professionally designed as this is fundamentally what sells your product on the shelves and big retailers will often not accept poor design, but as you mention you are at the concept stage you could always work towards hiring someone. To get started I would:
If you don't mind the difference in time zones, you can try outsourcing at odesk. The odesk job market is like ebay where the sellers (service providers) and buyers (employers) rate each other. You can post what your project, specify as much details as possible, deadlines, how much your budget is, etc.
The service providers, upon seeing your job posting will respond to your ad with their credentials as well as a proposal as to how much it will cost you. Give it a try.