I think aguijonazo hit the nail on the head in the comments. If you compare it to english, "this time" have the exact same ambiguities. Take these translations of your example:
- (Literal, unnatural) For this time's interview, I bought a suit.
- This time, for the interview, I bought a suit.
- For the interview, this time, I bought a suit.
- I bought a suit for the interview this time.
Now put these four [examples] sentences in each situations and see if it works.
- Past: "Did your interview go well?". Answer: "Yes, [examples], so I looked better."
- Present: "Is your interview going well? (asked while taking a break)". Answer: "Yes, [examples], so I look better."
- Future: "Your last interview didn't go well, are you ready for the one next week?". Answer: "Yes, [examples], so I should look better."
As you can see, we have the same problem in english. Context and verb tenses will give us the information we need. This means that your sentence can mean all three depending on context.
As a footnote, one interesting thing to realize is that, depending on the sentence structure, the isolated sentences gives different feelings. This is probably due to the frequency of usage of one particular form in certain situations. When I look at the literal translation of 今度の面接 (this time's interview), I can see why someone would translate it as "upcoming interview." Finally, in my limited Japanese experience, 今度の is also more often used for the next occurence (I have no proof of that, this needs confirmation).