Hard to tell from your screenshot where the problem is. Usually the first thing I'll try is dividing the dimensions by 12 to see if the dwg unit translator is off; using a foot instead of an inch or vice versa. I get 6.4' x 6'; I don't know the dimensions of the table, but does that sound right?
Google-ing the title of your object, I see the design is all rectilinear, see attached image. This would be very easy to model with slabs and then save as an object. Drag a fill the size of the top into the 2D window and then you can set a masking pen so you don't see the floor below. Take a look at the GDL beginner guides, specifically David Nicholson Coles Cookbook, and version will suffice for what you are doing. A search here will provide some links to the online version.
HTH
Erika
Architect, Consultant
MacBook Pro Retina, 15-inch Yosemite 2.8 GHz Intel Core i7 16 GB 1600 MHz DDR3
Mac OSX 10.11.1
AC5-18
Onuma System
"Implementing Successful Building Information Modeling"