Guide and small van Cape Coast-Takoradi

I'll be travelling to Ghana next May with a small group--6-8. Any suggestions for a tour company, etc. that could take us around? We'll start in Accra--we have a good line on accommodations, etc., there, but not for moving beyond. I would say we will be in the budget traveler category--willing to pay about $20usd for rooms.
However, I have no clue on how to locate a local guide/tour company. Any words of wisdom are appreciated.

The above mentioned village organizes just two trips-to Nzulezu stilt village(a stop at Elmina)and Volta region (Hohoe,Wli falls) and it's pretty expensive (around 200 euro per person for two days trip).