Symbian is not slow, it's just that the N8 does not have the faster hardware ever. Nor does it need it. For most use cases the phone is fast enough, while conserving the battery life so that it is more usable than any other smartphone in that range.
As for updated, PR 1.2 is available in most countries, so make sure to connect it to Ovi Suite and search for available updates.
Then again, since you are asking this in the programming category, it could be that your application has performance issues, in which case you should profile it and investigate the pain areas, then improve the algorithms used.