What head unit should i get?

I just got this subwoofer and amplifier for my 08 ford focus se.



Sub

http://cgi.ebay.com/LOADED-KICKER-SUB-BOX-W-CVR12-COMP-VR-SUBWOOFER-NEW-/130504872033?pt=Car_Subwoofers_Enclosures%26amp;hash=item1e62b25061#ht_3888wt_1139

Amp

http://www.google.com/imgres?imgurl=http://pacificstereo.com/media/catalog/product/cache/1/image/500x250/5e06319eda06f020e43594a9c230972d/k/e/kenwood_kac-7205.jpg%26amp;imgrefurl=http://pacificstereo.com/kenwood-kac-7205.html%26amp;usg=__EJkYGmW2Bf6BevmLPWJnvaBcfiw=%26amp;h=250%26amp;w=500%26amp;sz=57%26amp;hl=en%26amp;start=0%26amp;zoom=1%26amp;tbnid=3EsxoS9hkI5TBM:%26amp;tbnh=90%26amp;tbnw=180%26amp;ei=K5HATY3tIenn0QGj3YX0BA%26amp;prev=/search%3Fq%3Dkenwood%2Bkac%2B7205%26um%3D1%26hl%3Den%26sa%3DN%26biw%3D1366%26bih%3D667%26tbm%3Disch%26amp;um=1%26amp;itbs=1%26amp;iact=hc%26amp;vpx=483%26amp;vpy=198%26amp;dur=898%26amp;hovh=159%26amp;hovw=318%26amp;tx=169%26amp;ty=93%26amp;page=1%26amp;ndsp=18%26amp;ved=1t:429,r:2,s:0



So heres my question: Do i need to buy a new head unit? I heard i can just get a inline converter or something but would a new headunit make it sound better? What should i do? lol. Also if i do need a head unit can someone recommend a cheap, good HU? Also i dont want to have to order it online. Thanks for the help.What head unit should i get?
You don't have to get a new head unit since you already uses 08 model car, all you need is RCA Convector, which all I know close to a FM transmitter.