from

http://adsabs.harvard.edu/abs/2007PhRvD..75h4034K
So the size of the Universe is at least 24 Gpc. What is a Gpc you ask?

The parsec ("parallax of one arcsecond", symbol pc) is a unit of length, equal to just over 30 trillion kilometers, or about 3.261563378 light years.

Hence 24 * 3.261563378 = 78.277521072 light years.

**So the size of the Universe is at least 78 light years in diameter, possibly bigger, but apparently not smaller.**
How much of it can we see ?

Using Ho equal to 71 +/- 3.5 km/sec/Mpc

http://www.astro.ucla.edu/~wright/cosmology_faq.html#DN suggests the current best fit model which has an accelerating expansion gives a maximum distance we can see of 47 billion light years.

Pity the math link in the explanation does not work. :-(