So you have a Gmail address and you have a domain address as well and you want to send your domain email address without the " on behalf of " message that recipients see when sending emails through Gmail.
Gmail does allow you to use your own domain to send messages but it means delving into the settings in Gmail.
Open the settings section in Gmail which is in the top right hand side of Gmail
Now click on the accounts tab so you can see the email addresses associated with your account
Now you will see you email addresses in the Send mail as section
Then click on next step
You will need to contact your domain host to get the correct SMTP server information and explain to them what you are trying to do.
This information will vary depending on your domain name host
You will have a choice of 3 ports to use , choose the one that works for you, and enter your domain password ( not your Gmail password) as your emails are being relayed through your domain host.
Once you have clicked on save changes it will test what you have entered and if it is incorrect will give you a message that it is taking Gmail too long to respond or that the user name /password is incorrect. That means you have not entered the correct information.
Once you have entered the correct settings in the accounts section you will see the following
Sign up for a Gmail account
Setup your Gmail account on your current computer and make it an IMAP account
Here are the instructions from Google depending on the email client ( eg outlook,windows live mail,apple mail) you currently use.
Pay particular attention to the advanced settings for the ports
Redirect your current email to Gmail through your isp
This means logging onto for example Bigpond or Adam and redirecting your email address to your Gmail address
You will now have 2 email accounts on your computer your current one and your Gmail
Setup your Gmail account to match the folders for your current account , folders are labels in Gmail
When this is done , go to the folders in your current email account select all the emails in the folder ( ctrlA) and drag them to the corresponding label ( folder ) in Gmail
You can also highlight them all and ( Ctrl C ) and copy them to the label
You will then have moved all your emails to Gmail