Mentors are always available. Particularly entrepreneurs who have "made it" or who have retired and want to give back by helping others succeed in business. You can't succeed in business without receiving a little help and guidance along the way so most entrepreneurs enjoy returning the favour later in their careers.
The best place to find a business mentor is to look within your industry contact your industry association and ask for a contact list of owners of similar businesses to yours. Get in touch with the owners being careful not to choose a business in close proximity to you.
Consider joining a networking group, either face to face or online. These groups are great resources for finding people to guide your business development. Ask for help on LinkedIn. If you're not signed on LinkedIn the largest online network of business professionals in the world then get signed up.
Another source of mentors are your own professional advisors - ask your lawyer, accountant, insurance agent for connections to more senior entrepreneurs. If you don't ask, you won't find.