First of all, don't insult the camera by putting one of those rubber thingys on it. You can get near-original new hoods and lens covers from Fotodiox. They are very reasonable in price and very quick with delivery. Go on the 'Bay and look for item # 350245666363 for example. I have bought hoods and lens covers, straps and filter adaptors from them for both my Rollei's. And you'll need a lens hood - they do flare when pointed into the sun.
Second, The E2 model has a removable viewing hood and the screen is easily changed. The earlier E model (yours I believe) is a little trickier but not too hard. You have to remove the screws attaching the hood (the E2 has clips) to access the screen. I bought a Maxwell screen to replace the original one. Not cheap but much better, and instructions came with it. If you search around using Google you'll probably find a thread somewhere that tells you how to do it. Although I preferred Maxwell over Rick Oleson's screens, Rick has a page on his website headed "Focusing Screen Installation Guide" which will guide you, although it's a general instruction guide - not specifically for Rolleiflex.
Third, there are a few websites devoted to the Rollei.
One useful one is
http://www.rolleiclub.com/cameras/tlr/info/A-F_tlr.shtml
Fourth, if ever you're tempted to try messing with it yourself rather than getting it looked at by someone who knows what they're doing, you might find this useful - or off-putting! Go to
http://www.butkus.org/chinon/rolleiflex.htm and select the model you want.
Fifth, there is a downloadable copy of the Rolleiflex Service Manual - search for Rolleiflex_TLR.pdf. It's 63MB, so don't ask to have it emailed. Even more off-putting when you see the exploded view of all the parts!
There's a lot of information out there on the web and it's often more comprehensive than you'll get on RFF. You'd do yourself a favour to research both avenues - from RFF you get user experience and from the web you will locate useful documentation and sources.