Site conversion from win-1251 to utf-8

We have site that worked fine under CF5 all data keep in MSSQL (nvarchar field type), now we have to transfer site to CF8. The main problem that all data from DB appear as set of unreadable symbols. Target convert data in the DB from win-1251 charset to utf-8.
1.How can we make this conversion using standard assets without creation special script to make conversion.
2. OR is it possibly to force site to work normally with old win-1251 charset without any conversion.(now after site transferring all symbol unreadable).