In nighttime photography, the goal is to get as much light as possible, as 'fast' as possible.
That means lenses that have a maximum aperture size of f2.8 or larger. Remember, f-stops are 'reverse' numbered in that smaller numbers (ratios, actually) are larger apertures. Many of the higher-end, higher-priced zoom lenses have a minimum f-stop of f2.8, and maintain that f-stop thoughout the entire zoom range, whereas the EF 28-135 you have changes the maximum f-stop while zooming from f3.5 to f5.6 (way too small for night shots).
Alternatively, fixed focal length lenses, such as a 50mm f1.8 or f1.4, for example, open 'very wide' and capture a lot of light. F1.4 is twice as large an aperture as f2.8, and 4 times that of f5.6.
Depending on your budget, you may want to consider a Canon EF 16-35 f2.8L mark ii. I bought one shortly after I upgraded from a 30D to a 60D and was happy both with it's being 'wide enough' in cramped spaces as well as 'fast enough' (wide aperture) when needed. But that's about $1500 new. Although not as wide angle as the 16-35 can produce, a 'fast' 50mm or even 40mm lens would give better low light results without shutter speeds necessarily too slow to stop subject (and your) movement, causing blurred images. The 'nifty 50' f1.8 is perhaps the most economical of Canons' EF lenses.
Of course, you need not buy only Canon lenses. Canon compatible lenses such as those from Tamron, Sigma, and others offer similar focal lengths and apertures as does Canon, but at lesser cost. Used or refurbished lenses are another means of saving some money as well.
Low light photography in general requires 4 things...'fast' lenses (low f-stop numbers), slower shutter speeds (but not too slow), higher ISO speeds (but not so fast as to cause too much 'noise'), and perhaps and most importantly, a STABLE, steady hand / camera (ie, mono-pod or, better yet, tripod). Depending on the situation, an external flash unit would also be beneficial, as the built-in flash is useless after the first 10 feet and produces very harsh shadows and other negative lighting issues.
Most of all, don't go 'hog wild' and spend a zillion dollars on equipment annd not understand how and when to use it. Take it one step at a time. Start with a fast lens. See what that can and cannot do for you. Then decide what's needed next and take the next step.
