E.,
I have to agree with everyone else...don't rush it. He is only 1. I let my 3 year old use his bottle until he was about 18 months I transistioned from the bottle to a sippy cup (Avent) over those 6 months.
Use your best judgement....don't try to rush. I think you should do what your heart tells you...and that's always a good thing. Don't let your ped rush you and your son.
I started with the mid afternoon bottle...letting him get use to the sippy cup...and I used things like water and juice. Then I started using milk...it adjusted very well...but it was a 6 month adjustment. The Avent system is great because you can put the "sippy cup" nipple on the actual bottle...that way they are still holing on to the bottle. Then later you can transistion to the cup. I'm not sure what feeding system you are using...so be careful trying to give him a different kind of nipple....if he is anything like my son, it was one type of bottle ONLY...no exception!! :-)
RELAX...you are doing a wonderful job!! Be proud of yourself.