Let me be blunt... unless you devote a few years to studying it and you have some immersive experience, you won't be able to converse in the target language. Conversational language is simply too difficult to become proficient without putting in a huge amount of study time. Plus, the overwhelming majority of the people you'll interact with as a tourist will speak English far better than you speak their language. They'll prefer the easy interaction in English to wasting time trying to understand your attempts at their native tongue. It's always good to know a few polite phrases, but unless you're fluent, people with a job to do (ie, waiters, hotel receptionists, ticket counter sales clerks) just want the most efficient form of communication. And for most of Europe, that's English.
Not to discourage you from learning a foreign language. By all means, make the attempt. Being able to experience the world in a different language from your own opens you up to all sorts of new perspectives and ideas, particularly being able to read about news items that received little or no coverage in English-language media outlets. Do it as a long-term project for self-growth. But don't expect conversational fluency between now and the time you take your trip next spring.
I know nothing about Italian, but I'm fluent in Dutch and have a pretty good mastery of German (although I struggle to understand some of the regional dialects). German has a pretty steep learning curve, because the sentence structure is quite different from English, grammatical gender plays a very important role, and noun modifiers (articles and adjectives) have to be inflected for gender, number and case. And several other features, like separable verbs, the subjunctive mood, and the placement of verbs at the end of the sentence (it takes a while to get used to the main emphasis of a sentence coming at the end, rather than the begining, like English). Dutch has a similar sentence structure to German, but the grammar is simplified (ie, no case endings and grammatical gender plays a much less prominent role). The vocabulary often seems like an intermediate step between German and English. However, there's far less educational tools out there devoted to Dutch as a second language than German, probably because there's less of a demand.