We again took a local bus ´Puerto Iguazu´ which comes every hour (at the 30min). This bus costs 3 REAL takes you to the brazilian border where you have to get off and you need to get you passport stamped to leave the country.
Once this is done you would need to wait for the next bus - which you can use the same bus ticket, but it only arrives every hour. So we decided to walk across the border to the Argentina side which was about 2km long. YES with all our backpacks. Easdy you just follow the road. It helped that we met a great Israeli couple to chat with.
After getting stamped on the Argentina side, you then just in time to catch the next hour bus ´puerto iguazu´ which takes you to the main central bus terminal. Which is close to all the main places.
Easy as! Took 2 hours and a bit only!