What is the quickest way to get a HK visa?

I am a Ghanian passport holder, and I need to travel to HK.

I am told that it quicker to get my entry permit from HK visa office in HK by my local sponsor. It takes at least 4 weeks to 3 months to get a HK visa in Ghana.

Can I apply my HK entry permit in Ghana China Embassy? or Do I have to go to Nigeria to apply for it?

Thanks a lot!
Anna