Here's how: Paste the hardware ID into a search engine such as Google and look at the results. Sore results show that the Hardware ID is for BCM94318MPG chipset which is IEEE 802.11g chipet. Because of that, I'd say that it doesn't support 5 GHz range. You're looking for devices which support IEEE 802.11a. Some IEEE 802.11n devices will support 5 GHz radio, but such devices will also support IEEE 802.11a standard.
I could be wrong though, but I don't see another remote way of finding required information in this case.
There are sites with PCI vendor and device databases, but Google will usually list them if they have any info and this is not the case.
You could try with some hardware ID utilities like SiSoft Sandra and similar and hope they provide a result on with GNU/Linux live CDs and lspci command which may give some more interesting information like chipset for example.
I myself have Intel 4965AGN and it has no special indication of 5 GHz network capability. The networks just show up when they are in range. You could also go to device manager and look at deice properties and hope that 5 GHz is mentioned somewhere, but it looks like you already did that.