If your plan is to use a handgun for home defense, train hard in its use. Train beyond punching paper. Train in low light; train from behind cover/concealment. If you are insufficiently equipped, you must overcome it with proficiency.
Lokpyrite and Crosshair's idea of using the shotgun as an opening volley was my first thought, but I would be concerned about flubbing the transition when under stress.
You can train to transition from a carried long arm to a holstered handgun, but this is not usually the arrangement in a home defense situation. (See Old Marksman's post).
, I would probably feel equally comfortable and confident sticking with the handgun only. If I had time to really hunker down I would consider opening with the shotgun.
Until I can muster up more money
For less than $200 dollars and a trip to Wal-Mart you can have a more than adequate home defense weapon in the Maverick 88. If you feel undergunned, there are no excuses. This is not a new video game system or Egyptian sheets we are talking about. Quit eating out for a month or two.
"Before all else, be armed."