With a wired and a wireless connection and a typical desktop operating system, you probably won't be able to use the two connections simultaneously to make a single faster connection to your network. Desktop versions of Windows leave that functionality to the network driver, and there aren't a lot of network cards that can do it. It probably wouldn't help much on a home network anyway unless you're moving huge amounts of data back and forth amongst multiple computers.
But you can bridge the two and turn your computer into a makeshift wireless access point as you said. You can also make your computer into a makeshift router using ICS