i came to usa on fiance visa..and i got married three month ago and applied for adjustment of status..can you tell me how long it ll take for adjustment of status.

i have done my fingerprints with them... i have few questions to ask

when will we have to go for interview?
what do they ask in interview?
and will i have to have a medical examination( i already did one in my country when i applied for fiance visa)?
and how long this process takes?

answeres to above questions will be exteremly appreciated.

thanks in advance

how long your AOS will take depends on the service center at which it was submitted. some are a little faster than others, but on average I would say around 18month.
you can find out more about processing times for the various service centers at the USCIS website.
at one point you will get mail from the CIS asking you to schedule an appointment for the interview. how long that will be also depends on the service center at which you applied.
to the interview you bring evidence to show that your marriage is in good faith. so bring wedding pics, bills that you have together, shared bank-account etc. the specific questions that you will be asked are at the discretion of the immigration officer. but if your marriage is in good faith, just be honest and you shouldn't have anything to worry about.
I'm not sure about the medical, since you had one done abroad. medical exams are usually good for 12 months.
for more 'personal experience' and waiting times for the different service centers check out www.immigrate2us.net a lot of the users there have time-lines posted, plus lots more information specifically for marriage based AOS