The US was very tired of war in April, 1945, and funds were starting to be short. The Russians had about three times as many divisions in Europe as the US albeit smaller ones. Russia had much better tanks, comparable fighters, very tough experienced soldiers, and ton of artillery. Patton would not have "marched to Moscow". It would have been an incredibly tough fight, probably ending in stalemate.
You might say "Well, we had the bomb", in August anyway, but not many of them, and only transferrable using the B-29, which was hardly immune to opposing fighters and not really tactically useful. And we didn't have many of them.
I don't think it was at all a viable option to have attacked Russia in 1945. We still had the war in the Pacific going on as well.