Hopefully you are working with a Realtor to help you with this...after looking closely at the actuals, then start looking at how this home fits in with your lifestyle...then you can get an idea of what you would like to offer, for the value needs to be a good value for you and yours, not simply the nuts and bolts of a building.
We need to know some more information. Your buyers agent should be doing this work for you, but anyways...
1) Where is the house? At least, what section of Clifton is it in?
2) How long has it been on the market?
3) When did it sell last and for how much?
4) Is it on a busy road or near a railroad or highway or industrial or commercial zone?
5) Is it for-sale-by-owner? If it is, you should reduce the offer by x% right off the top since the seller is not paying a commission.
6) Is there adequate parking for both apartments? This affects rent, which affects value.
7) Is the seller unduly motivated in any way (divorce, bankruptcy, relocation, long time on market, bought something else, other difficulties?)
8) Is the basement finished legally?
9) Are the utilities separate for each apartment?
10) What is the zoning for the area. Can the house be rebuilt as a 2-family if destroyed by fire?
11) What is the real condition of the home? New kitchens? New baths? New roof or siding or windows or heating system, or electric?
12) Where is the oil tank?
13) Any other locational problems (flood zone, environmental issues near property, etc)?
14) What is the rent roll for the property for the past 5 years? Has it been consistently rented?
15) What are the expenses of the property? How much income does it generate after expenses? And how does that income and expense profile compare with other recently sold 2-family properties in the neighborhood?
As you can see, there is a lot that goes into deciding upon an appropriate offering price on a 2-family dwelling in Clifton. Most of it has nothing to do with you. The property has a fair market value based on the factors above, and several more I haven't mentioned. If you need further help with this contact me through my website.