I purchased a new head unit and I just took my old one out about half an hour ago, only to realize both the radio antenna jack and the wire harness are larger on the old head unit and won't fit into the new one.

Is there a way I can solve this without buying a different head unit, such as getting adapters or something? Not having radio wouldn't be the end of the world, but I kind of really need the wire harness to fit into the new head unit.

New head unit(top) and the old one.
http://postimg.org/image/76mmrtxhn/

Any help would be greatly appreciated as the installing of my stereo and subs will be postponed until I figure this out.
http://www.ebay.com/itm/2001-2006-Select-Hyundai-Complete-Aftermarket-Radio-Install-Dash-Kit-PKG290-/330850553960?pt=Motors_Car_Truck_Parts_Accessories &vxp=mtr&hash=item4d083ad068

also, above is the new dash fitting and wire harness,
I'm not even sure if I'll need the wire harness or not, or if it's even the right size for my new head unit?

( 2003 Hyundai Sonata GLS, 4dr V6)