IAS has mainly three phases - preliminary exam, mains exam and then an interview. For the prelims questions are of objective type nature - from General Knowledge and once topic of applicant's choice from the list of areas mentioned.It is usually done in May-June. Results of prelims are out in July and short listed students can apply for Mains exams in October. Main has 9 papers - one of the Indian languages, English, Essay, GK, Current Affairs and then 2 papers from optional 1 and optional 2 subject choices specified. Successful students will be called for an interview. It is a well organized exam structure and it is bound to test your in-depth knowledge in the areas you have chosen. There are good IAS training academies like Seshans Academy, they can guide you through the process.
Please visit some sites: http://www.onestopias.com/subjects/ http://www.civilserviceindia.com/current-affairs/index.html
As far your first query is concerned it has been resolved. Regarding the next one I will say that If you join Rao classes at Delhi for IAS it would be best & cost around 80000 to 1 lac. But it is better to do the CA and IAS in two diffrent shots not simultaneously because it needs the deep knowledge of GK & GS.
There are many coaching institutes are in India who providing classroom course as well as correspondence course. Fee structure depends upon what subject you have chosen because fees are different for different subjects.