Hopefully we're done off topic and you can get some answers to your original question.
I would suggest you post some additional information regarding your workflow, calibration (monitor and/or printer), inks (OEM or not), paper, etc. so that the community can provide some better guidance regarding your specific issues. I'd also suggest you try posting a small copy of an pic that is exhibiting the problems you are describing along with a scan and/or picture of the print that illustrates what you are seeing.
In particular, I'd really try to be specific regarding your workflow process and settings from beginning to end.
Oh, and you are asking about two different problems. #1 is the monitor/print match. #2 is what is happening to your files when posted to a web site. With #2, again examples would help (originals for download/comparison to a site link). Have you tried pulling the file off the web site and into Photoshop to see if they still match, off line?
Unfortunately, as you have probably guessed from reading this thread, monitor/print matching is not an easy thing and it may not be something that can be diagnosed on a forum. Also, it may not be cheap to resolve, so you may have to make a decision between the costs of "accurate" and "close enough".