Will new adsl router increase speed?

Yes this is possible, I have seen the same happen with my router. I have a Belkin N1 Vision adsl router and the best I can get at home is 8.5 - 9Mbps. When I set up a new connection for my sister with this mickey mouse ISP provided router the locked at 11Mbps. That was something I wasn't too happy to see, but what can you do...
A new router will probaby just give you a few Mbps more than the one you already have, so if you can't bear the fact that you could be boing a bit better plan an upgrade when you can.

It's possible. Your WAG160N is an older unit, with most likely out of date / flawed firmware. Not saying newer stuff will be any better, but it should be.

You also mention your current router / modem has been acting up. If it's not something that can be easily fixed with a configuration change, firmware update etc... now would be a good time to upgrade to a current model with better / faster networking..

The specs on your machine show that it is draft 802.11n, not final, your wired ethernet connection types aren't specified, which would tell me that they are most likely fast ethernet (10/100) instead of Gigabit...

If you can afford to upgrade, this is a good opportunity to do so...

First things first, unless you absolutely have to have a combo unit, you are typically better off having your modem and router as 2 separate devices. The integrated units seem to have a reputation for slower performance, and higher failure rates. Probably due to the added heat of the additional circuits in the same space...

Whatever setup you go with, try to get something running at least Wireless N600 or better, with gigabit wired ports...

Don't get me wrong. I totally understand the appeal of combination devices. Fewer things to connect, less total space consumed / I.E. less clutter. I totally get it, but consider the advantage of going with a more modular approach. With a modem and router separate, you don't have to replace an entire combo unit to get the next upgraded features you may want such as faster wireless N such as simultaneous dual band, or gigabit wired ports.... and the modem itself, if you have trouble with that, you only have to replace the modem and you are up and going again, instead of having to reconfigure your network all over again...

well after posting this I found that I could get Fibre via Plusnet so I have ordered it for the 18th, but this now gives me more questions as I have two "hot spots" running in my Hotel,

I am hoping that as my current system I can just feed the internet via an ethernet to the access points and all will be well.
However I have read that you need "fibre" wifi units as my current units are not designed for fast connections ?.

Does anyone know?

Thanks

Uh. Fibre? I am guessing you are in the U.K. so I am unfamiliar with the specifics of your technologies over there. That also explains a lot about the router / modem combo as those are much more popular in Europe than here in North America.

I have looked at the Plusnet website and the documentation is quite confusing. They appear to provide a modem and router for you.

Since you mention multiple hot spots and a hotel, I am assuming you have WAPs (Wireless Access Point)s in a commercial hotel / bed and breakfast type establishment. I am a bit lost as to what to tell you on how to configure multiple WAPs using their equipment. By the same token the requirements they list state that "cable routers" that support PPoE, and have an ethernet uplink port such as the Cisco / Linksys EA series would work. They also recommend wireless N for wireless connections. The EA4200 is a great router for that application. I am not sure about the EA3500 and I have the EA2700, which is a good router, but I suspect the signal strength would be insufficient...

You would then want to add a range extender. The Cisco / Linksys RE1000 would be a good choice. It's a simple WiFi radio repeater that will really boost your signal...