First you need the formula to find density, which is d = PM / RT.
Convert 807 torrs to atm by dividing by 760 torr. 807 torr x (1 atm / 760 torr) = 1.06 atm
Then find the molar mass of carbon dioxide, which is ~44g.
R is a constant. (~0.0821)
Convert 98.0 degree C to K, with is 98 + 273.15 K.
The plug everything in and you are good to do. Also remember that mL=cm3.