Hi,
I am DotNetNuke expert. Before getting into project, can you please share the URL if possible or list couple of issues you are facing. This way, I can get prepared and then we can discuss the actual fixes for your issues.
Generally upgrade issues can be categorized as following:
1 - UI/Skin related issues which can be solved easily
2 - Issues related to Custom Modules with source code
3 - Issues related to Custom Modules with no source code
I can help you with #1 and #2 - if there are some issues that falls into category# 3, we might need to get in touch with the original developer of the custom module.
Ping me if you want to discuss this project further, thanks.
FYI: I am in Malaysia these days (same time-zone as yours).