You could perhaps try our Expat forum to get answrers from those who have already made the move.
You can find the forum if you click here

If your looking to rent long term (3 months or more) my advice would be to book a package holiday for 2 weeks, and look while you are here.... there are always notices on lamposts, and on supermarket notice boards etc. A long term let will be much cheaper obviously than a weeks price. If you can find a long term place online you will generally pay a finders fee (unless you deal direct with the owner.... which is doubtful). You will usually be asked for a month up front, and a months deposit (Returnable if you dont trash the place, and you give notice!!!)
Depending on where you want to go you will be looking at on average 400-500 euros per month for a studio, and 500-650 euros per month for a 1 bed, but as i said this will vary lots with location.
The dog may also be a problem, as lots of places won't allow animals. I can't tell from your post if you intend to stay for good, or just to live here a while, but be advised it is quite an expensive ordeal to bring a 1 dog here let alone 2 if your not planning on staying for a good length of time!