Electric space tug

I would like to have you sketch get some numbers for a space tug to go from LEO to TLI.
As it passes the moon it will hand off the payload to a tether and then go back to LEO empty.

Please use some of the following thruster in designing the space tug:

Turion TIE-20 GEN2
  Thrust: 55 mN
  ISP:  4500
  Power: 2000 watts
  Price: $150000
  $/mN:  1899
  Mass: 23 kg


It will use solar power.

We want the payload to be 1000 Kg. 

We want to get from LEO to passing the moon (not orbit) in 1 year or less.

We want to look 3 different possible reaction masses: 
  1) Xenon
  2) Krypton
  3) Argon  

Please make a table showing estimated ISP for each of these 3, exhaust velocity, and price/kg to buy on Earth.

Please figure out how much reaction mass this takes on the way there, and on the way back.   
If we replaced the tank each flight what is the total mass of the tank and reaction mass.  

Please make a table with the masses of all the parts of the system and estimate the costs, 
and also totals.

For the case of the "disposable space tug" please include:
    1) the whole cost of the tug including thrusters, solar, reaction mass and tank, etc.
    2) the launch costs to LEO for the whole space tug.

For case of "reusable space tug" just include the costs of:
    1) cost of tank full of reaction mass purchased on Earth
    2) cost of launching the tank of reaction mass to LEO
    3) cost of launching the payload to LEO

We imaging the costs to LEO when we launch might be:
     HighCost = $1000/kg
     LowCost = $200/kg

For each of the 3 reaction mass types, please list the total mass launched, total costs (both launch and other costs as above)
and also the total costs divided by 1000 to see what cost/kg of payload is in the following cases:

1) disposable space tug at HighCost
2) disposable space tug at LowCost
3) reusable space tug at HighCost 
4) reusable space tug at LowCost

Try to do a "time value of money" for both the space tug and the payload and see what that would 
add to the best $/kg payload number from above.

Please output your whole answer in html so I can put it on a website.