Well the best solution would have been to repipe the kitchen properly as part of your renovations. It is clear that you are not into sweating pipes or installing pex yet, but that is what I would have done. At this stage to get the water back on I would recommend installing this type valve and consider doing it properly soon.http://www.watts.com/pro/_productsFu...pid=5315&ref=2
It is a push on connector that will go on the Poly-Butylene and adapt to a faucet/dishwasher/icemaker/etc. supply. It will certainly work better than what you are trying.
I would also recommend installing braided stainless steel supply lines.