We have earlier posted about standalone package of Ovi Store for Symbian^3 when the version 2.12.043 was available to download manually. You can check the post here.
It seems that the same link will provide every next latest Ovi Store update available for Symbian^3. We just found the same link now delivering the version 2.12.045.
Following is what JasonBlack posted earlier on Ovi Daily App
You should now have the latest Ovi Store client. How can you check it? If you open the Store on your Nokia smartphone and check the version under the Account Tab > Help > About, you should have a version number of at least 2.12.xxx.
However, some of you with new Symbian phones (e.g. Nokia N8) were unable to complete the installation of the latest Store client. If this happened to you, the Ovi Store team has released a stand-alone installation package which contains an updated version of the Ovi Store client. It also updates some middleware used by the Store and many other apps.
You can download it from http://lr.ovi.mobi/store/client-symbian-3/ directly to your new Symbian device. When prompted for the installation destination, please choose the C: drive. Confirm all prompts during the installation. Note that additional middleware components may be downloaded to your device if they require updates.