In proverbial "round numbers", mortgage payments on the average home in Portland next year will be about $200/month more than today if this forecast increase in mortgage rates is correct. (To check the forecasting accuracy of these sources, I looked up their January 2012 forecast for January 2013 – they were within 0.2 of today's average rates.
That's to buy at the same price. If home prices go up 5-6% as predicted, it's even more.
To go beyond "round numbers" and see what it would cost you to buy that real Portland-area house you want today, I can introduce you to a good mortgage broker. Between the two of us, you can see real numbers and real homes for you. Call or text me at 503-505-9722 or @DaveSuttonHomes