An update in autumn is highly unlikely, as an update is expected in January/February 2011, but a November update might happen. If the 13" MBP gets an ix CPU, it also has to get a dedicated GPU, as Intel does not allow Nvidia to make the chipsets for its ix CPU line.
Use MRoogle to find hundreds of threads about this.
If all you do is basic tasks, the C2D will more than suffice, even in four/five years.
There are still many people out there using G4s in their iBooks/PowerBooks, since yesterday we also have a working G4 PowerMac at work again, running Avid Media Composer to digitise hundreds of tapes.