What is your house worth?
Is it worth the 280K that you owe?
Is it worth putting in the additional 250K?
Do you intend to live your life out there?
How is your Credit Score?
Do you have a lot of other Financial Obligations (Debts)?
You mention that your Job is insecure - is that common knowledge?
(for example, is the News Media
running stories about your company or industry or employer going out of business, or fixing to declare
In other words, if you used your $250K to pay down the existing Loan down to $30,000
would you be able to refinance the house if you wanted to get money back out?
(If you re-financed a $30,000 loan the payment would be peanuts).
What are you earning on that money now?
In better times, you would leverage or invest the $250K to make more money.
But times have changed; good investments are hard to find.
There are many who would advise you to put the entire $250K toward your existing Mortgage.
Then it is safely invested in your home.
With the continuing Economic Collapse, and now the Cap and Trade Nightmare looming on the horizon,
your American Paper Dollars may soon be worthless.
Tough Decision - Best wishes on it.