First issue is, you're not going to transfer "live" HD video via USB 2.0 connection. You can transfer files after the recording, but not usually during.
Second, there are capture cards such as BlackMagic Intensity or Matrox MXO2 Mini that will accept an HDMI input and capture high-quality live video to the PC. However, many DSLR cameras, even though they have an HDMI output, will put out a non-standard signal. Meaning it is cropped, or perhaps has some viewfinder info overlays in the picture which can not be turned off in the menu, making the HDMI output unsuitable for recording. This has been a huge problem for DSLR film makers that want to use external recording devices like the Atomos Ninja 2. Some of the newer DSLRs can now output a proper, recordable signal, after much complaing from customers.
Bottom line, money is always a factor, but a DSLR is the last camera I would ever try to use for long-form events. There has to be something you can borrow or buy cheap second-hand, meaning a camcorder. But even then, you need some kind of capture card to get the live video into the computer, unless using a DV or HDV camera and then you can use 1394 (Firewire) into computer. DSLRs are just not practical for a lot of video tasks, sorry.
Thanks for the info. We're a new church so we don't have much of a budget for video equipment yet. We've been trying to limp along by stopping and starting every 12 minutes haha. The T3i is actually my personal camera that I never intended to use for this kind of thing so it wasn't a factor when I was buying. There's stuff like magic lantern out there and I was hoping there was something that would allow direct pc recording. I would much prefer a camcorder anyways but those are a tad pricey. I guess we'll have to wait until we can drop a couple grand on a camera haha.
Don't give up so fast.
Connect your camera to your HDTV cia the HDMI cable, Does the video look good to you? No overlays? Then look at a card that captures HDMI like Jeff suggested.
I could probably get rid of those lines with magic lantern