Indudual Visa Requirment

I am srilankan. Myself and my sister are planning to visit beijing. We already contacted a travel Agent in China and she is going to arrange our trip. She will submit a letter to embassy to confirm our trip and request to grant visa for us. Please clarify me whether we can apply indidual visa for us by ourself with that letter? Do they need financial record alone with our application? If so howmuch it should be?

Thanks so much. Appreciate your kind reply.