Well - good luck to you!!! Having two with different ages to train will be very challenging, for sure. If you go into the beginning of the Training forum you will find a lot of information on housebreaking. There should be a couple with links to different helpful websites, such as:
www.thehousebreakingbible.com www.ehow.com/how_2316690_housebreak-dog-seven-days.html www.sidekickdogtraining.com/training_tips_free
I have two also, but did not have to housebreak them both at the same time. I use the peepads and found it the easiest for me - but everyone is different. I have them sleep in the laundry room with their food and beds on one side and their peepads in another. I have found treats helped me a lot with a lot of praise when they go where they are suppose to. Don't yell when they have accidents - but if you do catch them in the act - just stomp your foot, clap your hands and say "NO" loudly. That should stop them from going and then you pick them up and bring them to the pads. Most than not - they won't go - but at least they are getting the idea that - that is where they are suppose to go.
Good luck to you! And - I'm sure you are going to hear it from others - but since your ittle guy isn't fixed - you may never housebreak him.