Filing income from profession + salary

In the financial year 2011-12, I worked a few months as a salried employee in an Indian company and I got a Form 16 from my company. 

For the rest of the year I worked as a software consulatant to a foreing company and I get payments againt the invoices I sent to them. 

I have a  4Laks salaried income and 14 lakshs professional income. Do I need to audit the income?

For my case, which ITR form I should use for filing the income?

Can I claim the depreciaiton of a motor car (personally own)?

Thanks in advance.