Well, For making the website for any agency, offices etc, you need to find a good company or a freelancer, who can understand your needs and ideas what the travel agency will provide to the customer. If the person who don;t understand what exactly your plan or idea about the travel agency, he might not give the right presentation to your website.
Here are the steps you can do.
1. Calculate your budget
2. Find a local agency according to your budget
3. Find similar companies like you have and give the reference sites to the developing company etc.
4. provide them the information about your company and ideas etc.
If you need further assistance you can always write to me firstname.lastname@example.org