Boring or not, you need to concentrate on it until you've got it down. You are extremely lucky that you only need 5WPM now. I had to take 13WPM for my General both sending and receiving and without the second chance with written questions. I had a similar problem after I frittered away my Novice privileges on 2 meter voice without doing much HF CW. Then the Novice expired. I got the Tech but it didn't allow me to use HF CW at all.
Anyway, you might check your local ham club because many if not most of them offer code classes. Listen to W1AW daily on the air and download their recordings from WWW.ARRL.ORG
website to your PC or iPod. That works pretty well because they also provide the text files to verify your copy. You can buy courses with tapes, etc. but spending time with it should get you to 5WPM very quickly. The time will be required no matter what you buy.
I found the punctuation characters the most difficult to remember and you will have punctuation characters in your test so get them down too.
Personally I now spend most of my mobile HF time in the CW portions of 17, 20 and 40 meters. I've found that speeds that were leaving me with my mouth open a year ago are actually readable now. I'm using a Vibroplex Iambic paddle key with a Kenwood TS2000 from my truck for my two hour daily commute to work.
You won't regret getting your General. It opens a whole new world of ham radio for you.
As a VE, I can vouch for how much easier the code test is now. You only have to receive at 5WPM plus you can pass even if you don't copy enough contiguous text by answering the written questions about the message.