I can understand your pain, as I have been there couple of times :). But, patience is the key here brother. The thing is Duet is not so popular here so it does not get sold like Mehran/ Corolla. You have to wait a bit longer. BTW there is very slim chance that you would find someone willing to exchange honda/ toyota with this one, anyways, BOL. Dealers are the ones to get your car sold quick, but, the con is you will get ripped off of your car's true worth.
Don't know your location, but, I guess each city has its own car markets (like in KHI there is a sunday car market in north KHI and Defence). Those are best locations to meet a potential buyer. Make sure that your demand is reasonable and for that you have to do a market survey for the very same brand you have. Second, make it presentable :D, no offense, I mean get it washed/ polished, install tire covers if it don't have already or have alloys, do interior cleaning. You can do these things in hardly around 1-2K. For selling online you have to take multiple/ good photos in daylight and make sure that you cover almost each side of the car including interior and engine room. Then try Seller's section here on PW or do place an ad on PW and on other forums too.
Those were just some tips from the top of my head. I really do wish that your car gets sold quick at best possible price