It would appear that what you are looking for is a Profile provider. This can be used to store addition information about users such as first and last names and other miscellanea.
in Web.config
<profile>
<providers>
<clear/>
<add name="AspNetSqlProfileProvider"
type="System.Web.Profile.SqlProfileProvider"
connectionStringName="yourConnectionString"<!--Same as membership provider-->
applicationName="/"/>
</providers>
<properties>
<add name="FirstName" type="string"/>
<add name="LastName" type="string"/>
<add name="Company" type="string"/>
</properties>
</profile>
Add/edit profile properties:
var username = User.Identity.Name;
ProfileBase profile = ProfileBase.Create(username);
profile["FirstName"] = "John";
profile["LastName"] = "Smith";
profile["Company"] = "WalMart";
profile.Save();
Read profile properties:
var username = User.Identity.Name;
var profile = ProfileBase.Create(username);
var firstName = profile["FirstName"] as string;
var lastName = profile["LastName"] as string;
var company = profile["Company"] as string;
I think this would be the way to go and a bit cleaner and easier to maintain that using comments.