Ask for funding before or after applying I finished my master in computer science about 2 years ago... 
And I just started to apply for PhD... I have received a prompt reply to one of my email and I really don't know what should I do!? here is the response : 

"Dear Ali,

It is impossible for me to know over a year in advance whether I will take any students for Fall 2016.  Your CV looks interesting and I encourage you to apply to the program so you are eligible for any potential openings."

I asked for admission on fall 2016 but maybe I could ask for winter 2015 too... 

Should I ask for funding now or after applying? How should I reply him?
Your question really contains two parts: about funding and about what to do with the email. @vonbrand already answered the funding part, so I will answer the other half:

This is really a rather common reply. If you apply for the fall 2016, you will likely take courses for the first year, so you're looking for someone who may start to be your adviser in the fall 2017 -- two years from now. I have no idea how my funding situation will look like that far out, nor whether I will gain or lose any graduate students until then. In other words, I cannot promise that (i) I will be able to support anyone financially this far out, (ii) I will have the mental and time capacity to  accept more graduate students this far out. At least in the US (and likely in Canada), you can't generally expect to have an adviser lined up before you even apply to a graduate program -- you have to apply and accept admission to a department in the hope that when you need one, an adviser will materialize.