I believe the "AspDotNetStorefront" text is coming from the value in your StoreName AppConfig, you can change that in the Store Configuration Wizard or in Configuration > Advanced > AppConfig Parameters (search configs for 'StoreName').
The (Test mode) text in the subject will also go away once you set your store to use live transactions. Also available in the Configuration wizard or AppConfigs, search for 'UseLiveTransactions'.
I wouldn't recommend removing the (Test mode) from the string resource, it might make it difficult for you to tell which orders were taking while your store was in test mode and which were taken in live mode.