That upgrade is likely to cost you a lot of money (unless you know somewhere to get it cheaper), but what will you gain?
I happen to feel that W7 is not a huge improvement over Vista. I have 2 Vista PCs and one W7 PC and I think Vista is fine on both boxes. I know Vista got a bad reputation at first, but it is now a fine, stable operating system.
You are likely to spend £150 or so to upgrade to W7 Ultimate (according to Amazon) and I just dont think it is worth it.
With Office, it depends what components you use. Do you use things like Access and Publisher ?.
Office 2010 is out now, so best going for that, but the Office 2010 Professional package will cost you about £350 which I think is scandalous.
The Office 2010 Home and Student version can be got for less than £100, but that only includes Word, Excel, Powerpoint and OneNote. It can be installed on 3 PCs.
Only you can say if you use Office and Windows enough to justify the outlay, but to me it is a lot of money for little gain.