If the door bellow is twisted, it may just be a simple matter of a clamp that has come loose allowing the bellow to shift. If its the front clamp located around the door opening, this can easily be resolved by removing the clamp, repositioning the bellow and reinserting the clamp. If its the rear clamp, however, you may have to remove the front of the washer to gain full access to it. There is an aligment mark (arrow) on the bellow at the 12 o'clock postion where it meets the wash tub. You need to make sure the arrow is pointing straight up. The following link explains how to replace a bellow:
Use this link even if you do not decide to replace the bellow. It provides good information on how the bellow is installed. Bottom line, if the bellow is not leaking, and you can resolve the twist, you do not need to replace it. Make sure you inspect for cracks or tears. As far as the additional components are concerned, inspect the clamps that you have before buying new ones. I've only had to replace these clamps on rare occasion. Last of all, "Yes", this is a job for a do-it-yourselfer. Its a little time consuming, but can be accomplished easily by following the link I provided. If you have questions, please let me know. I hope this helps you.
PS You may check repairclinic.com to see if they carry the bellow at a lower price. They offer competitive pricing and often carry the SAME part for less.