Sounds like a cop-out, but WiFi coverage is dependent on a lot of factors: type of construction, size of your estate, placement of the Time Capsule, nearby metallic objects (for example, forced-air heating ducts in the walls), other radio equipment (in particular cordless phones operating on the same frequency band), presence of other WiFi access points in the neighborhood, etc.
In general, the answer is probably yes. You'd want the Time Capsule in a central location (not in the furthest back corner of the house, not in the basement).
I have a dual-band Airport Extreme, whose WiFi radio is pretty much the same as in the TC. It's located in a central location on the 1st floor of my 2,000 sq. ft. house, and it gives me good coverage everywhere except in the farthest room over the garage.
will the range of this router will be enough to cover my 2 floored house?
Questions like this always boil down to the the same answer......you will not know how the wireless device will perform in your home until your try it out there.
For that reason, you should understand the store's return policy in advance before you buy.
As a very rough guide......
A typical wall constructed of sheetrock and 2 by 4s will absorb....on average....about 15-20% of the wireless signal.
A typical ceiling will absorb 25-35% of the signal because of its more dense construction.
So, after 3-4 walls, or a ceiling and several walls, there won't be much of the wireless signal left.
I have about a 2400 square foot home, and it takes 4 AirPort routers to deliver the performance that I need.....a fast, very reliable wireless connection anywhere in the house and out in the patio area.