Need advice and possible paid consulting help for site development

I have been working on a site for a customer that is a combination shopping cart and informational site.
I have been successful setting up a theme, loading products, inputting articles and information and configuring various parts of the site.
However, I am running into obstacles that are taking me far too long to solve and I need advice on how to proceed.
Should I try to find resources to solve the problems and continue as I have been?
Should I try to find someone who is more of an expert to help me?
Can anyone give me approximate rates to solve problems?
I need help in a few different areas
1. configuring the UPS and USPS integration to the shipping part of the shopping cart
2. configuring the selection of articles and posts to create the best and easiest user interface
3. configuring a professional and usable home page
I hope that this post is ok - and I appreciate any advice offered
thanks
richard
rich@gms.com