You can download the "superpatch" from the link at EA's
Sims 3 forum. Then, copy the patch to a USB thumb drive, DVD (or other portable storage) and run it on your non-Internet connected computer. The superpatch contains all patches for the game, expansions and stuff packs that EA has released, so they tend to be large. The current 1.48 patch is over 1 GB, so make sure you have enough space.
Hope this helps and happy Simming.
Flynn