You don't need a lawyer, I was told the average person actually does it all on their own, not everybody can afford a lawyer and a lawyer is not a guarantee your appeal will get allowed, they just have more experience. Just start collecting everything you can to prove your relationship is genuine, and by everything I mean everything that has to do with you two, having solid proof is very important. Get family and friends to write letters to vouch for you two if they know your wife well. Acknowledge where you failed to provide enough information and proof (if you did) and address every concern they mentioned in their refusal letter, one by one. Overall, if you have a strong case, you will be fine without a lawyer.