Is a valid tourist visa enough to permit me the entrance in the US?

I am a university student in Ottawa, I'm in Canada with a study permit and


I have a Greek passport. Last year I traveled to the US in Christmas; my


tourist visa to visit the US was issued on November 10 2008 and it expires


on 01 May 2010. However, on my passport there was also stapled another


permit, a small white card with my name, birth date, and citizenship,as well


as a 11-digit departure number and a date (Jun 21 2009).





I only know realized that on the back it is stated that I had to "surrender this


permit when I leave the U.S." and that "Failure to do so may delay your entry


into the U.S. in the future", and this card was giving me permission to stay in


the US until June 29, 2009.





I was planning to visit the US (Hawaii) in mid-December for a couple of weeks..


So, my visa IS valid, but





1) Do I have to obtain some other permit? I guess the visa itself is not enough


to permit me the entry in the US? Like this small white paper..





2) Can I return this old permit that expired on June 29 2009 now to somebody?


Does the fact that I didn't return it when I left the US will have any consequences


for my future entry in the US?





It seems rather impossible to contact somebody from the embassy, but I am trying. Meanwhile, if you could enlighten me on the questions above, I would be really grateful...|||By failing to turn in the I-94, you have made it appear that you are still in the U.S. As you have left the United States and are still in possession of the I-94, it is in your best interest to forward it to the appropriate authorities so that your record is corrected and that you do not experience any problems on future travel to the United States as a result.





It is very important that you complete the back of the card listing the port of departure and date of departure from the United States and the carrier/flight information. The I-94 together with a letter of explanation and evidence of your departure from the U.S. should be sent to:





DHS-CBP SBU, 1084 South Laurel Road


London, Kentucky 40744


USA





You can also send:





Original boarding passes you used to depart the United States;





Entry or departure stamps in your passport to indicate you entered another country after you departed the United States (please copy all passport pages that are not completely blank and include the biographic page containing your photograph);





Dated pay slips or vouchers from your employer to indicate that you worked in another country after you departed the United States;





Dated bank records showing transactions in your home country to indicate that you were in another country after your left the United States;





School records showing your attendance at a school outside the United States to indicate you were in another country after you left the United States;





Dated credit card receipts with the credit card number deleted for purchases you made after you departed the United States to indicate you were in another country after you left the United States.





You can show this same evidence to the inspector in December when you try to go to Hawaii. Mere possession of a visa does not guarantee admission.