Wifi interface changes name seemingly at random

Question

I'm currently having some issues getting a wireless interface to work continuously under an install of Ubuntu 12.04.1 LTS.

Some of the issues I'm experiencing include

• Connection will drop out after some time after it has initially worked.
• Interface will be a different name after a reboot. For example, wlan0 will become wlan4 when using the ifconfig -a command.
• Ubuntu will take a long time to boot, looking for network adapters.

The purpose of this build is to function as a web kiosk in a library. The computer is supposed to boot up into a web browser, and allow for browsing of the catalog. For some reason this interface does not appear to be working as it should.

Are there any explanations for some of these problems I'm having, and perhaps some solutions?

The wireless card appears as this after doing an lspci ...

Ralink corp. RT2561/RT61 802.11g PCI

In the /etc/network/interfaces file I have the following configuration for the interface.

auto wlan0
iface wlan0 inet dhcp
     wireless-essid UDwireless
     wireless-mode Managed 

Thanks in advance for help on this.

--edit (added output for /etc/udev/rules.d/70-persistent-net.rules)

# PCI device 0x1814:/sys/devices/pci0000:00/0000:00:14.4/0000:02:01.0 (rt61pci)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:1f:1f:d6:33:d1", ATTR{dev_id}=="0x0", ATTR{type}=="1", KERNEL=="wlan*", NAME="wlan0"

# PCI device 0x14e4:/sys/devices/pci0000:00/0000:00:14.4/0000:02:09.0/ssb0:0 (b44)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:1a:a0:24:2c:c4", ATTR{dev_id}=="0x0", ATTR{type}=="1", KERNEL=="eth*", NAME="eth0"

# PCI device 0x1814:/sys/devices/pci0000:00/0000:00:14.4/0000:02:01.0 (rt61pci)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:1f:0f:d6:33:d1", ATTR{dev_id}=="0x0", ATTR{type}=="1", KERNEL=="wlan*", NAME="wlan1"

# PCI device 0x1814:/sys/devices/pci0000:00/0000:00:14.4/0000:02:01.0 (rt61pci)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:1f:1f:d6:31:d0", ATTR{dev_id}=="0x0", ATTR{type}=="1", KERNEL=="wlan*", NAME="wlan2"

# PCI device 0x1814:/sys/devices/pci0000:00/0000:00:14.4/0000:02:01.0 (rt61pci)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:1f:1f:c6:33:d1", ATTR{dev_id}=="0x0", ATTR{type}=="1", KERNEL=="wlan*", NAME="wlan3"

# PCI device 0x1814:/sys/devices/pci0000:00/0000:00:14.4/0000:02:01.0 (rt61pci)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:1f:1f:d6:33:d0", ATTR{dev_id}=="0x0", ATTR{type}=="1", KERNEL=="wlan*", NAME="wlan4"

--edit - output of lspci

00:00.0 Host bridge: Advanced Micro Devices [AMD] nee ATI Radeon Xpress 200 Host Bridge (rev 01)
00:01.0 PCI bridge: Advanced Micro Devices [AMD] nee ATI RS480 PCI Bridge
00:12.0 SATA controller: Advanced Micro Devices [AMD] nee ATI SB600 Non-Raid-5S ATA
00:13.0 USB controller: Advanced Micro Devices [AMD] nee ATI SB600 USB (OHCI0)
00:13.1 USB controller: Advanced Micro Devices [AMD] nee ATI SB600 USB (OHCI1)
00:13.2 USB controller: Advanced Micro Devices [AMD] nee ATI SB600 USB (OHCI2)
00:13.3 USB controller: Advanced Micro Devices [AMD] nee ATI SB600 USB (OHCI3)
00:13.4 USB controller: Advanced Micro Devices [AMD] nee ATI SB600 USB (OHCI4)
00:13.5 USB controller: Advanced Micro Devices [AMD] nee ATI SB600 USB Controller (EHCI)
00:14.0 SMBus: Advanced Micro Devices [AMD] nee ATI SBx00 SMBus Controller (rev 13)
00:14.1 IDE interface: Advanced Micro Devices [AMD] nee ATI SB600 IDE
00:14.2 Audio device: Advanced Micro Devices [AMD] nee ATI SBx00 Azalia (Intel HDA)
00:14.3 ISA bridge: Advanced Micro Devices [AMD] nee ATI SB600 PCI to LPC Bridge
00:14.4 PCI bridge: Advanced Micro Devices [AMD] nee ATI SBx00 PCI to PCI Bridge
01:05.0 VGA compatible controller: Advanced Micro Devices [AMD] nee ATI RC410 [Radeon Xpress 200]
02:01.0 Network controller: Ralink corp. RT2561/RT61 802.11g PCI
02:09.0 Ethernet controller: Broadcom Corporation BCM4401-B0 100Base-TX (rev 02)