Just went through this a number of weeks ago.
Presuming you have bought anything yet, I would put a figure of over 10k on it. You could be talking twice that depending on the quality of the items.
One very important thing is the price of the little things. We must of spent over 1k in Building Suppliers buying things like tile adhesive, glue, nails, tile cutter, grout, paint, brushes, polybond, drill bits, masking tape, spirit level, poddle (a great invention), white spirits, scraper (a must have) etc etc.
These are the things which are going to bite you. I really couldn't believe the amount we spent there.
You are also talking about 700-800 for cooker, 800 for decent carpet for hall stairs & landing. 400 for fridge, 750 for wooden floors. Tiles - a few thousand if you wanted. I think we spent about 1k on our bathroom and the WC only came to about 40 Euro (floor and splash tiles behing basin). Bed would be anywhere from 300 up. We paid about 600 as we don't want to replace it anytime soon.
Big money for couch and chairs. You might see a couch for sale for about 700, but the arm chairs can cost almost as much. You may want to budget about 2k. Dining room table and chairs - about 200 if you want cheap. Remember that you will end up replacing a lot of stuff a lot sooner if you get cheap stuff.