My understanding is that you will not be able to import UK data files from Quicken 98 into Quicken 2010 without using Money first (if you can get a copy which is doubtful). I very much doubt that it will update UK share prices. I lost that facility with Quicken 2004 when Intuit ended all UK support. See this thread near the end about the snags Quicken review
It is a pity because Quicken was an excellent program and I still use it but not to the extent I did. You may well be advised to look at other UK financial management programs. Home Accountz, etc. Business Accountz may be more suitable for invoices. I have used either though.