The price of a company's stock at any given moment is established by a ratio of buyers to sellers. When the sellers outnumber the buyers at a given price, the stock price drops until there are enough people willing to buy the stock to balance the equation again. When there are more people wanting to purchase a stock at a given price than people willing to sell it, the stock price rises until there are enough sellers to balance things again. So given this, it's easy to see that a very large fund (or collection of very large funds) buying or selling could drive the price of a stock in one direction or another (because the sheer number of shares they trade can tip the balance one way or another).
What's important to keep in mind though is that the ratio of buyers to sellers at any given moment is determined by "market sentiment" and speculation. People selling a stock think the price is going down, and people buying it think it's going up; and these beliefs are strongly influenced by news coverage and available information relating to the company. So in the case of your company in the example that would be expected to triple in value in the next year; if everyone agreed that this was correct then the stock would triple almost instantly. The only reason the stock doesn't reach this value instantly is that the market is split between people thinking this is going to happen and people who think it won't.
Over time, news coverage and new information will cause one side to appear more correct than the other and the balance will shift to drive the price up or down. All this is to say that YES, large funds and their movements CAN influence a stock's trading value; BUT their movements are based upon the same news, information, analysis and sentiment as the rest of the market. Meaning that the price of a stock is much more closely tied to news and available information than day to day trading volumes. In short, buying good companies at good prices is just as "good" as it's ever been.
Also keep in mind that the fact that YOU can buy and sell stocks without having a huge impact on price is an ADVANTAGE that you have. By slipping in or out at the right times in major market movements you can do things that a massive investment fund simply cannot.