Split system Heat Pump

I live in a house that is 18 years old that currently has a heat pump and the exchanger? (under the house part) is starting to rust out. Some of my ducting under the house is also starting to sag and drip water here and there. The unit works just fine for now. We recently had a valve replaced on the outside part that cost about $400 to fix. The house is a two level home with 1600 sq feet and is located in the NC piedmont area. We plan on selling this house and moving within the next two years.

My questions are:

Should we replace this unit now or just keep patching it up and hope the new buyer doesn't demand that it be replaced? I'm thinking that if I was a buyer and knew the heat pump was about out, I might reconsider the purchase altogether.

If I replace it, what size and seer should I consider for this size of home? I don't need top of the line, just adequate will be fine.
Who would make a good middle of the road model for my needs?

Ballpark what my total cost would be. I realize you don't have all the information necessary to give a written estimate, just give me an idea of how many new batteries I'm going to have to buy for my pacemaker!!

Thanks for your help.

Ahh...depending on the home inspector you get when you go to sell, you might have to replace it anyway. We just did 4 in Salisbury due to almost the same senario you stated.

If the ducts leaking water, you got issues...and you will prob have to replace it as well.

Umm...its called a manual T and you are gonna be hard pressed to find anyone around here to do it. I started charging when I realized I was doing the other, larger companies homework. Min SEER you will find in this area now is 13. 10s, 12, are gone. They are out there, but why in hell you wanna pay more for something in high demand by the hacks than you would for a proper system.

Anyone.

Depends. Ive priced myself out of jobs I didnt want. Depends on how nasty your crawlspace is and what an ass you are during the estimate. Honestly. You wanted information, now you have it. Also, expect to pay for an estimate now that fuel is hitting $3 a gallon in Greensboro, Winston, and High Point areas.

And no, Im not looking for your business, even tho I am in your area. Our guys have enough to do now without adding to it. Besides, Im like Paul, another usenet asshole that really wont give you much in teh way of free advice, since we work our ass off for those that do pay, and you are price shopping....you wont like our prices.

Good luck tho.