To add two more harddpoints you will need the UTF editor (downloads) and your BiniQDU stuff. Now suggest you read a tutorial on adding hardpoints - as it i can't be arsed to explain it again (kinda lenghty explanation). The tutorial is called something like 'adding extra hardpoints' - surprised? hehe
Once you have added the two hardpoints you will then need to declare them in the shiparch.ini (also look at newb needs help - i gave an example of this in there!!). Do this and you will have your two new hardpoints. To move the turret you just need to change the position values using UTF in the ships CMP.
Now to give it a bigger power source, open the goods.ini in your equipment folder and scroll down to where your ship is. Once you find your ships hull package <--note package
Eg (this is the humpy)
[Good
nickname = rfr_package
category = ship
hull = rfr_hull
addon = ge_rfr_engine_01, internal, 1
addon = rh_freighter_power01, internal, 1 <--your power supply
addon = ge_s_scanner_01, internal, 1

Change it to whatever power supply you are after - something like the dragon should give you more than enough power for a defender based fighter
[Good
nickname = ke_package <-- dragon
category = ship
hull = ke_hull
addon = ge_ke_engine_01, internal, 1
addon = ku_elite_power01, internal, 1 <---power
addon = ge_s_scanner_01, internal, 1

So if you made this change (using the humpy example) you would see
[Good
nickname = rfr_package
category = ship
hull = rfr_hull
addon = ge_rfr_engine_01, internal, 1
addon = ku_elite_power01, internal, 1 <--new power
addon = ge_s_scanner_01, internal, 1

Of course i shoulda been bothered to look for the defender instead to be helpful - but you can figure it out. Any probs with the UTF then just repost and i will take some time to explain what to do!
Chips
p.s Remember to 'save as' for files, and you will have to buy your ship again for the new power (but not the new mounts)