I Need a C# and Unity Weapon Script Written for prototype game

General information for the business: For a Unity 2d Game
Kind of development: Customization of existing program
Description of requirements/functionality: I have been building a prototype game and need a weapons script added in.

The inventory system I am using is https://www.assetstore.unity3d.com/en/#!/content/26310

I have enabled the character system, inventory, Crafting and hotbar.

I would like the weapon system be integrated with this system. I now small amounts of c# However this is above my level.
When I Equip a Weapon (Gun or Melee) with this system, it should show the sprite and have the ability to fire weapon. It should also incorporate different types of ammos so that the gun will not shot without ammo.

Dont worry about assets, use basic 2d boxes as its still in prototype. Just work on having the system work with 4 start weapons:

A Melee
A HandGun
ShotGun
Machine Gun

No Assets are needed, just use basic boxes

So after having a little play myself I have managed to get little further, so with the Inventory Manager I have added a new prefab setting called "Item Model Hold"

http://i.imgur.com/z23ybNl.png

And I have added a New Sprite Render and added it to the script:

http://i.imgur.com/HZ1tat7.png

So all thats left is that when a weapon is equipped, it calls the Preffab Item Model Hold which will contain the sprite and the weapon script:

http://i.imgur.com/Am4pjbr.png

Let me know if you know of a better way else, send me a price.

Everything should be documented as I will be adding to the script myself at a later date.
Specific technologies required: Unity5 2d
OS requirements: Windows
Extra notes:

To keep it basic I need:

Weapons integrate with my current inventory system
Ammo and reload scripts
4 different weapons as a start

Regards