asylee appeal od decision of the immigration judge

An asylee applicant denied has the right to appeal the decision of the immigration judge. I would Llike to ask the following questions:
1. Do I need an attorney in this proccess?
2. Can I apply for employment authorization at this point?
3. How long does the appeal prccess take usually?
4. Are there cases that have been granted after the appeal and what is the percentage?
thak you for your advice.