The new passport will be stamped. The old passports r not valid and cannot be used for any immigration purposes.
Also, Indian counslates hold passport renewal camps and if there is a camp in your city, try to attend them and your passport might be renewed the same day. Also even though Jan 2005 is another 7 months away, you can still get a new passport. Call the Indian counslate for this. If you mail your documents, you will get a passport in 10-14 days. They are very efficient.