simple returns / autogressive model


I have a problem with solving this statistical matter.

The file aexdaily(1) consists a couple of data, the closing prices (workdays) of the AEX-index (the Dutch equivalent of the Dow Jones index, only a lot smaller) for the period 25 april 2004 - 24 april 2005. Transform the values into simple returns Rt.
Estimate the first order autoregressive model Rt+1 = µ + ρ(Rt - µ) + εt+1.

This is what I found out:
Rt is normally distributed with mean µ + ρ(Rt - µ) and standard deviation σ (which is the standard deviation of εt+1)
well, I thought the µ (mean) is 343,47
εt+1 = σ = 16,98
the ρ is this matter is the population coefficient of correlation and I don't know how to know this number.
I can't go on know and I an not really sure that this is ok. Does someone has any ideas how I can solve this problem?

Thanks in advance.
E. Cools