andybangkok

My english writing is not too good as I am a French Canadian.
I have received from the school all the papers needed for an Education visa. Tomorrow June 6, I have a flight to Udon Thani and then made my way to Vientiane.  
I have just learned when reading the forum and according to the person who went there last April ,that Vientiane don't give multriple entries, even if the formule have an entry for these entries.
I have also look at the Royal Thai embassy site and according to them it is possible to have multiple entries for 5,000 on a study visa:

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3. NON-IMMIGRANT VISA
   1. REQUIREMENT
This type of visa is issued to applicants who wish to enter the Kingdom for the following purposes:
  
   - to study, to come on a work study tour or observation tour , to participate in projects or seminars , to attend a conference or training course , to study as a foreign Buddhist monk (Category "ED")

2. DOCUMENTS REQUIRED
  
   2.1 The applicants must submit the following relevant documents depending on the purpose of their visit.
- Visa application form completely filled out
   -  Passport or travel document with validity not less than 6 months. The validity of 18 months is required for one year visa application.- (4 x 6 cm) protograph of the applicant, taken within the past six months

Transcript / Letter of acceptance from the concerned schools/universities or institutes ("ED") 3. VISA FEE
  
   2,000 Baht for single entry and 5,000 Baht for multiple entries.
  
   4. VALIDITY OF A VISA
  
   Single-entry and multiple-entry visas are valid for three months. Multiple-entry visas could also be valid for one year
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I have to go to Montreal, Canada July 8, 2011 and my ticket are already purchased .

So I come back from Laos, have a ed visa 3 months stamped in my passport & have to extended it for one year by going immigration every 3 months.
But in 1 month I go out of the country
If they don't give me the multi-entries in Laos ,even if I am willing to pay 5,000 baht, what can I do?
Can I go to Chang Wattana and ask for multi entries  even if it's only 1 week that I have just receive the ed visa?

Thank you in advance for your answers