I used too much malt. What should I do? Suggestions how to salvage?

Sounds like your OG was in the 1.060-1.065 range, which is fine. Did you taste it? If your fermentation is stuck it will still taste sweet like wort.

I would not add anything, just give it more time. And as others have mentioned, a hydrometer or refractometer will be the only way to know for sure where you are.

Since you don't have a hydrometer, it will be hard to tell what's really going on. But likely, what happened is that your fermentation got "stuck". In other words, let's assume the recipe's OG was 1.060. John Palmer estimates that each pound of DME yields 40 points of extract per gallon of water, or about 8 points per 5 gallons. Assuming you did a 5 gallon batch, that means you added 24 extra points. In other words, our hypothetical 1.060 beer is now 1.084.

This really isn't a huge deal, but as you likely used a typical "light" beer yeast as opposed to a more robust "heavy" beer yeast, your fermentation likely stalled between 1.020-1.030. This means your beer will be very sweet and "thick" due to all the residual sugars.

Your options are, as you have mentioned, to dilute the final beer in order to bring down the sugar content per volume. This will also dilute the alcohol content (which may not be a bad thing). Alternatively, you could just drink the beer as-is, maybe blend it with a lighter beer when you serve it (I've done this before, it was actually rather interesting). Finally, you could try purchasing some champagne yeast to finish out the fermentation as well.

Each of these options (except the "do nothing" option) will impact the final flavor of the beer. For better or worse is purely a subjective matter.

To close, it is extremely unlikely that you have "ruined" your beer. The fact that you have any bubbling at all indicates that fermentation did probably occur, meaning alcohol was produced, meaning that most bacteria are likely dead. My recommendation is to try it, see how you like it, then decide what to do from there.

You didn't mention it in your question, but I'm assuming that you've made a 5 gallon batch.

When I put those ingredients into Beer Smith, it shows a starting gravity of 1.062, which is perfectly reasonable for an IPA. Let the beer finish fermenting. It will probably take a week or two longer than a lower gravity beer, so be patient. In the end you'll have a beer with slightly higher alcohol content, and slightly more body.