There should be no problems after 24 hours and that includes the site of the cath entry for the stent implant. I was hospitalized for 3-4 days from heart failure, and I had a stent implanted at that time. I felt so good I almost sprinted out the hospital door.
You should not be experiencing any problems related to the stent implant procedure. It may be a good idea to followup with your cardiologist to rule out blood clots and/or infection.
I would go to your GP and get it checked out. There is usually something put into the site known as Angio-seal and takes about 90 days to gradually dissolve. Bruising can occur and in the 6 procedures I've had, none have lasted more than four days. Stiffness in the leg lasts with me around two to three days if I don't exercise by gentle walking. That's my experience tho, and I'm sure everyone is probably different. The bruising by your knee doesn't sound right to me, it should be much further up. Did they enter your artery in a lower position than usual?