Hitachi 42 Pd3000 Plasma

A bit of help, please, as not too technical!
Have just purchased the above, have a Sony DAV S400 (all in one DVD and sound system) and Sky Digibox to attach.
Potential problems
1.Sony DAV S400 has only basic connections and DVD fairly basic, despite this feel that it gives reasonable reproduction of AV on my current Sony TV.
2.Normal Arial signal poor.
3. After purchase have very little funds to upgrade any compontents.
Please can anyone recommend best way to hook up the system and what needs to be purchased
Thank you.
RADDERS